21C Physics

Q1: Here is some data about planets

Look at the data in the table of planets. Which pieces of information would you use to argue that Neptune is slightly denser than Uranus?

1. The masses
2. The diameters
3. The distances from the sun

Q2: Which of these distances would an alien be most likely to understand?

Q3: An object on the Earth is pulled more towards the Earth by Earths gravity than it is is pulled towards the Sun by the Suns gravity. Which of these quantities should be included in the explanation

1. The masses of the Sun and the Earth
2. The distance the object is from the Sun and the Earth
3. The materials surrounding the Sun and the Earth

Q4: A total eclipse of the Sun is rare at any particular location on the Earth. Which of these reasons can explain why?

1. The Moon's shadow is roughly the diameter of the Moon, when it falls on the Earth
2. The plane of the Moon's orbit varies between plus and minus 5 degrees of the plane of the Earth's orbit
3. The Moon is responsible for tides

Q5: The light energy that is emitted by a meteor comes from . . .

Q6: When the nuclei of light elements combine, energy is released.

In order for nuclear fusion to occur nuclei have to get very close together. Normally atoms cannot get very close together because the electrons surrounding each nucleus repel one another. In a high temperature plasma the electrons are stripped off from the atoms leaving just the nuclei. However nuclei are positively charged and repel one another. In order to get them close enough together to fuse they have to be travelling at very high speeds. Once the process has started the energy released from each fusion will help to keep the temperature high.

Nuclear fusion is difficult to achieve in the laboratory because of

Q7: Fig. 2 shows observations made in June and December being used to calculate the distance to a nearby star. Which of these statements are true?

1. For this star, June and December are the best time to make observations
2. If the observations were made in August and February the angle would be larger
3. For another star the best times could be April and May

Q8: Which of these statements about galaxies is true?

1. we can measure the speed with which galaxies are moving away from us, by examining the radiation they emit
2. moving galaxies only emit red light
3. galaxies can occasionally move towards each other

Q9: Some of these statements only contain data and some contain explanations. Which only contains data?

Q10: Although the Earth is spinning so that the equator moves round at 1700 km/h, water and objects on the surface do not get flung off. What is the best explanation for this?

Q11: Which of the following locations can make the observations in a telescope clearer?

1. In a well-populated area
2. A place with low rainfall
3. At high altitudes

Q12: The Earth has a good deal of motion energy as it moves around the Sun. Where did this energy come from in the formation of the Solar System?

Q13: The Andromeda galaxy is about 2.5 million light-years away from the Earth. It is made up
of 1000 billion stars.
How long does it take light to reach the Earth from the Andromeda galaxy?

Q. This question is about earthquakes and the structure of the Earth.

An earthquake occurs at X.
The diagram shows places where S-waves and P-waves from the earthquake are detected. Which of these statements explain this pattern of observations?

1. S-waves cannot travel through liquids
2. S-waves are slower than P-waves
3. Part of the Earth's core is liquid

Q15: Which of these steps is not used in order to estimate the distance to a star from its apparent brightness?

Q16: Why is it so difficult to work out if the gravitational attraction between the galaxies is sufficient to stop the expansion of the universe?

1. It is difficult to know the total mass in the galaxies because of the amount of dark matter
2. It is difficult to measure accurately the distances to other galaxies
3. Any change in the rate of expansion is too small to measure

Q17: Which of the following are properties of P-waves?

1. They are transverse
2. They can pass through liquids
3. They are slower than S-waves

Q18: New rocks can form from old rocks using which of the following processes

Q19:

The diagram shows the surface of water at the moment a wave is passing. Use the measurements given to work out the amplitude and the wavelength

Q20: Betelgeuse is one of the brightest stars, although it is over 600 light years away. It is nearing the end of its life and is expected to go supernova. When it does it will explode sending out radiation and particles at enormous speeds. The shock wave will travel at 10% of the speed of light. Which of these statements are true

1. When it does explode it will take 600 years until we can detect the explosion
2. The shock wave will take 5400 years to reach us after we see the explosion
3. It may have already exploded

Q21: A fairly common, very bright type of star called a Cepheid variable pulsates regularly. For example the brightness might go from very bright to dim and back to very bright in a fixed time, say 5 days.

It was noticed that several Cepheids in another galaxy (the Large Magellenic Cloud) were pulsating at different rates but those which pulsated slower were brighter. Why was this an important discovery?

1. It gives a way of comparing the actual brightness (luminosity) of some distant stars
2. It tells us what will happen to the Sun
3. It helps us to count the number of stars in a galaxy

Q22: When earthquakes occur, S-waves and P-waves are produced which travel through the Earth. The diagram below shows the direction travelled by an S-wave moving through the ground.

Which arrow shows the way the ground vibrates as the S-wave moves through it in the direction shown above?

Q23: What causes the new Moon to look bright?

1. It reflects light from the Sun, from all the surface we can see.
2. It is at its hottest when new
3. It has a radioactive core

Q24: When these events are arranged in order with the most recent first, which one appears in the middle?

Q25: The rate of gravitational collapse of gas and dust is likely to increase once it has started, because . . .

Q26: The Moon has features which we can see when they are illuminated, but we only ever see the features on one half of the Moon. There are features which were never seen on the other half, until spacecraft went past the Moon. This is because . . .

Q27: Which of the following processes is NOT part of the Rock Cycle?

Q28: When Wegener presented his theory of continental drift it was not accepted by other scientists.

Which statement(s) give the reason(s) for its rejection?

1. There were simpler explanations for the same evidence
2. The same type of fossil could be found on different continents
3. The movement of continents could not be detected

Q29: In the 1920's astronomers and other scientists made new observations and tried to explain them.These statements build a story about how scientific explanations develop.

Which one is 

Scientists develop the explanation further and predict other outcomes

Q30: Which planet lies between Jupiter and Uranus?

Q. Who came up with the theory of Continental Drift?

Q32: What causes tectonic plates to move?

Q33: Which of these does NOT orbit the Sun?

Q34: Which of these is true for S- and P- waves?

Q35: Here are three statements about meteoroids. Which of them uses the emphasized terms correctly?

1. An asteroid can be deflected from its orbit, and approach the Earth as a meteoroid.
2. A meteorite  could land on the Earth
3. Shooting stars are really meteors

Q. When radiation emitted by the Sun strikes an object, which of the following will not happen

Q. Which of these is true for digital signals

Q. The temperature of a fixed mass of gas is increased from 200 kelvin to 600 kelvin. The volume remains the same. What will happen to the pressure?

Q. If hydrogen gas gets hotter the molecules speed up until they collide with each other so ferociously that they break up into hydrogen atoms. Further heating increases the collision forces so that electrons can be removed during collisions. A plasma is a mixture of hydrogen ions (protons) and electrons moving at very high speeds. Further increases in heating can enable protons to collide and join together.

1. this is known as fusion
2. more energy is released when protons join
3. the fused particle is neutral

Q. A typical star like the Sun will spend the longest time as a . . .

Q. Which of these processes decreases the amount of carbon in the atmosphere

Q. A skydiver leaves the plane at a height of 5000 metres and does not immediately open his parachute. The faster he falls the bigger the drag. When he gets to 2000 metres he opens the chute and glides to a gentle landing

At what height does the skydiver fall at the greatest speed and at what height is the acceleration greatest?

Q. What has to happen before a main sequence star begins to fuse helium?

1. the hydrogen has been used up
2. a white dwarf has formed
3. a red giant or supergiant has formed

Q. When two identical heating elements are connected in series to a 12 volt supply they draw a current of 2 amps. When they are connected in parallel they draw a current of 5 amps. How much more power will be supplied by the second arrangement?

Q. Which of these fuels will be able to generate the most power from a kilogram?

Q. One of the limitations of thermal power stations is that the steam has to flow and provide a big force on the turbine blades. This is achieved by reducing the pressure of the steam after it passes through the blades, by condensing it. The cooling towers provide cold water for this purpose. Of course the cold water in the cooling towers gets heated up. That is waste energy but cannot be avoided. The best power stations are only about 60% efficient because of this reason. Typically the steam is heated to 800 kelvin in the boiler and the cooling water ends up at 300 kelvin

It has been suggested that the warmed water from the cooling towers could be taken away and used in nearby towns as a cheap source of heating.

Q. To boil enough tapwater for a particular teapot requires 300 000 joules. What is the power rating of a kettle that does this in exactly 5 minutes?

Q. The diagram shows an almost frictionless roller coaster. A chain lifts the car up the first slope then it runs down and up the other slopes. Its position is marked at four places. At which place will it have the slowest speed and at which place will it have the fastest speed?

Q. Which of these are describing analogue rather than digital?

1. the number of different values it is possible to transmit is unlimited
2. a slight change to one of the waveforms sent might have no effect on the signal received
3. waveforms transmitted are curvy rather than straight

Q. Which of these does not use X-rays?

Q. Four objects of different masses are moving at different speeds

1. 8 kg moving at 5 m/s 40 100
2. 12 kg moving at 4 m/s 48 96
3. 15 kg moving at 3 m/s 45 66.5
4. 25 kg moving at 2 m/s 50 50

Work out their momenta and their kinetic energies.

Which of these statements is true?

Q. This graph is a Hertzsprung-Russell diagram used for comparing different stars. The vertical axis represents the luminosity (absolute brightness) of a star. The curved arrow represents the progress we expect the Sun to make after it stops fusing hydrogen. 

Identify the star groups

Q. "Nuclear medicine uses radioactive tracers to find out what is wrong with a patient. 
Gamma emitting radioactive materials, with a short half-life, are used as tracers to 
examine blood flow in a patient’s body.
One tracer used is technetium-99 (Tc-99). It has a half-life of 6 hours. It only emits low 
energy gamma rays, which easily escape the body to be detected by gamma ray cameras. 
These cameras feed information to a computer which builds up a picture of the path 
taken by the tracer through the patient’s body.
Tc-99 can be given to a patient by mouth or by injection. It produces no discomfort and 
after a few days there is no sign that the test was ever done."

After reading this a patient asked for more reassurance. Which of the statements below is not correct?

Q. A gas boiler converts 65% of gas energy supplied into heat energy in the water.  A domestic electric water heater converts 90% of  electrical energy consumed into heat energy in the water.  The electricity is supplied by a gas fueled power station with an efficiency of  70%. In choosing a boiler, which of these considerations are valid for the householder?

1. the overall efficiency in converting energy from gas is 2% better using the electric boiler
2. the cost of gas is usually less than electricity
3. gas can be more dangerous in the home

Q. One of the disadvantages of nuclear power is the need to dispose of the radioactive waste safely?. 

Which of these statements uses the words irradiation or contamination incorrectly?

Q. In 2013, a householder paid £720 a year for electricity. Amongst other things the electricity was used to heat water. On January 1st 2014, a salesman suggested he had solar panels put on the roof to provide hot water. The solar panels would cost £2 550 and save £150 per year on his electricity bill.

The salesman claims that the householder will get his money back in 17 years

What other information does the householder need to make a decision?

Q57:. Here are three types of rock . . .

• sedimentary
• igneous
• metamorphic

. . . and three specific rocks

1. marble
2. sandstone
3. granite

Identify each rock as an example of one of the three types.

Q58:. Heber and Harlow both want the same trophy. It is a platinum ball weighing 200 newtons. It has been lifted up off the desk but Heber is pulling it to the left and Harlow is pulling it to the right.

There are three forces acting on the ball and it remains exactly where it is.

In which direction is Harlow pulling?

Q59: A 'carrier wave' is used to send a signal as an electromagnetic wave. The carrier wave is modulated by the signal as in the diagram to make the wave that is transmitted

In this example, which of these statements apply?

1. the transmitted wave has a fixed frequency
2. the carrier frequency is much higher than the signal frequency
3. the amplitude of the transmitted wave is steady

Q60: A digital signal is transmitted by sending a wave of two frequencies. A high frequency is used for the 1 and a low frequency for the 0.

Here are the waveforms

Q61: Which type of power station takes the least time to start up?

Q62: A car accelerates from rest and reaches a speed of 30 m/s in 5 seconds. What acceleration is that?

The Earth in the Universe

distance = wave speed x time

wave speed = frequency x wavelength

Sustainable energy

energy transferred = power x time

power = voltage x current

Explaining motion

momentum = mass x velocity

change of momentum =
resultant force x time for which it acts

work done by a force =
force x distance moved 
(in the direction of the force)

amount of energy transferred = work done

change in gravitational potential energy =

weight x vertical height difference

kinetic energy = ½ x mass x [velocity]2

Electric circuits

power = voltage x current

Radioactive materials

energy = mass x [speed of light in vacuum]2

Q69: This diagram is an attempt to explain how a digital signal can be sent using an analogue wave.

The frequency of the waveform is changed. One frequency corresponds with ON and a different frequency for OFF

Which of these statements is NOT true

Q70: A small firework is launched vertically. This graph shows the height of the rocket at any time. 

The rocket explodes at time Z

When is the acceleration zero?

Q71: The skydiver is moving under the influence of two vertical forces. 

Air resistance is upwards, opposing motion

Weight is 750 newtons downwards

The skydiver is currently moving at terminal velocity .

Which statements is/are true?

1. the speed of the skydiver is increasing
2. air resistance is equal to 750 newtons
3. the skydiver has zero acceleration

Q. A forklift truck raises a load of 300 newtons onto a platform 2 metres high.

How much work has the truck done on the load?

Q73: What is the symbol of a component that conducts better when light is shone on it?

Q74: A circuit is connected with a battery, a resistor and a bulb, together with three ammeters.

Which of these statements about the ammeters is true?

1. A1 = A2 = A3
2. A1 = A2 + A3
3. A2 = A3

Q75: A magnet is dropped through a coil. The logger records the induced voltage as shown

What differences would have been observed if the magnet was dropped from a higher point?

1. the peak voltage would have been lower
2. the pulse would have taken longer
3. the pulse would have been a different shape

P6 - 1 Radioactivity

1. recall that some elements emit ionising radiation all the time and are called radioactive
2. understand that radioactive elements are naturally found in the environment, contributing tobackground radiation
3. understand that an atom has a nucleus, made of protons and neutrons, which is surrounded by electrons
4. understand that the results of the Rutherford-Geiger-Marsden alpha particle scattering experiment provided evidence that a gold atom contains a small, massive, positive region (the nucleus)
5. understand that protons and neutrons are held together in the nucleus by a strong force which balances the repulsive electrostatic force between the protons
6. understand that, if brought close enough together, hydrogen nuclei can fuse into helium nuclei releasing energy, and that this is called nuclear fusion
7. understand that Einstein’s equation E = mc2 is used to calculate the energy released during nuclear fusion and fission (where E is the energy produced, m is the mass lost and c is the speed of light in a vacuum)
8. understand that every atom of any element has the same number of protons but the number of neutrons may differ, and that forms of the same element with different numbers of neutrons are called isotopes
9. understand that the behaviour of radioactive materials cannot be changed by chemical or physical processes
10. recall that three types of ionising radiation (alpha, beta and gamma) are emitted by radioactive materials and that alpha particles consist of two protons and two neutrons, and that beta particles are identical to electrons
11. recall the penetration properties of each type of radiation
12. describe radioactive materials in terms of the instability of the nucleus, radiation emitted and the element left behind
13. complete nuclear equations for alpha and beta decay
14. understand that, over time, the activity of radioactive sources decreases
15. understand the meaning of the term half-life
16. understand that radioactive elements have a wide range of half-life values
17. carry out simple calculations involving half-life.

P6 - 2 Using Radioactivity

1. understand that ionising radiation can damage living cells and these may be killed or may become cancerous
2. understand that ionising radiation is able to break molecules into bits (called ions), which can then take part in other chemical reactions
3. recall and explain how ionising radiation can be used:
4. to treat cancer
5. to sterilise surgical instruments
6. to sterilise food
7. as a tracer in the body.
8. recall that radiation dose (in sieverts) (based on both amount and type of radiation) is a
9. measure of the possible harm done to your body
10. interpret given data on risk related to radiation dose
11. understand that radioactive materials expose people to risk by irradiation and contamination
12. understand that we are irradiated and contaminated by radioactive materials all the time and
13. recall the main sources of this background radiation
14. relate ideas about half-life and background radiation to the time taken for a radioactive source to become safe
15. recall categories of people who are regularly exposed to risk of radiation and that their exposure is carefully monitored, including radiographers and workers in nuclear power stations
16. understand that a nuclear fuel is one in which energy is released by changes in the nucleus
17. know that in nuclear fission a neutron splits a large and unstable nucleus (limited to
18. uranium and plutonium) into two smaller parts, roughly equal in size, releasing more neutrons
19. recall that the amount of energy released during nuclear fission is much greater than that
20. released in a chemical reaction involving a similar mass of material
21. understand how the nuclear fission process in nuclear power stations is controlled, and use the terms chain reaction, fuel rod, control rod and coolant
22. understand that nuclear power stations produce radioactive waste
23. understand that nuclear wastes are categorised as high level, intermediate level and low level, and relate this to disposal methods

Notice: 

John, Alex, Noah etc. If there are any readings or questions or answers which don't make sense to you then please email me at rjabbotts@gmail.com and I'll try to sort them out or explain.

There are over 600 questions so if one of them bothers you let me know the question id. You can find this by clicking on the Oh dear! or Well done! bar in the answers.

Good luck! Any feedback welcome.

Rich (Matt's Stepdad/Noah's Grandstepdad)

Q78: A parsec is a unit of . . . ?

Q79: Solar eclipses are quite rare because . . .

Q80: Which of the distances below is typical for neighbouring stars in the Milky Way?

Q81: Work out the distance to a galaxy if the recession speed is 1400 km/s

Use the relationship

speed of recession (km/s) =
Hubble constant (70 km/s per Mpc) 
× distance (Mpc)

Q82: When electrons in atoms jump between energy levels light of specific frequencies is emitted or absorbed. This allows us to identify elements in a star.

The different frequencies emitted (or absorbed) by a star are called . . .

Q83: On this Hertzsprung-Russell diagram, what type of stars are in region 2?

Q213: Here is some data about planets

A potato-shaped rock is discovered with a circular orbit of the Sun that takes 750 Earth days to complete. Where does its orbit lie relative to the planets?

Q214: A team of astronauts plans to arrive on the surface of the Moon when the Sun is directly overhead. Roughly how long will they have before the Sun sets so they can see without artificial lighting?

Q. Venus has an average surface temperature of approximately 480 °C.
The Earth has an average surface temperature of approximately 15 °C.
One reason for the temperature difference is the amount of energy that Venus gets from the
Sun. Why does Venus have a much higher surface temperature than the Earth?

1. Venus is closer to the Sun than the Earth is
2. Venus has no moons
3. Light energy spreads out as it travels further from the source

Q. S-waves travel at 3.6 km / s.
In a time of 5 seconds, the ground oscillates 40 times.
Calculate the wavelength of the waves.

Q. Which of these is NOT an electromagnetic wave

Q218: The diagram shows a seismic wave passing from the liquid core to the mantle.

Which of these statements is/are correct?

1. It is a P-wave
2. Y shows the reflected wave emerging from the core
3. The wave X travels faster than the wave Y

Q219: The vast majority of stars begin with a collapsing cloud of gas and dust which creates the conditions of temperature and pressure to begin fusion of hydrogen into helium. There has to be a minimum mass of the cloud.

If the mass is larger than that of the Sun the process still occurs but the temperature and pressure are higher and the fusion continues at a faster rate. The rate of fusion of hydrogen into helium is such to provide an outward pressure sufficient to balance the pressure from gravitational collapse.

The rate of fusion is steady until nearly all the hydrogen has gone. Although double the mass means twice as much hydrogen to burn, the increased rate of reaction burns the hydrogen at about 5 times the rate.

Which of these is/are generally true for stars with more mass than the Sun?

1. Have greater gravitational pressure
2. Have greater luminosity
3. Have longer lives

Q. Roughly how many stars are there in the Milky Way galaxy?

Q. An accumulation of hydrogen gas warms up as the centre of mass attracts all the other molecules and they speed up. As a gas which of these changes is/are happening?

1. the temperature is increasing
2. the volume is increasing
3. the pressure is increasing

Q. X-rays are useful because . . .?

Q. A geostationary orbit must

1. have a period of 23 hr 56 min
2. be directly above the equator
3. be orbitting in the right direction

Q. A professor has set up a matt black plate so that the Sun's rays fall directly on it. He measures the rising temperature of the plate every minute. Which of these statements is/are true?

1. the plate is an excellent absorber of radiation
2. the plate itself will radiate more and more the hotter it gets
3. when the plate is radiating as much as it receives from the Sun, it has reached its maximum temperature

Q. A farmer has solar cells installed on the roof of a barn.

The solar radiation received by the cells is 1000 watts.

The cells reflect 20% of the Sun's rays and absorb the rest.

The efficiency of the cells converting absorbed rays to electrical energy is 30%.

What is the power output?

Q. Four wave patterns of radiowaves from a star are shown below. Each graph shows the same time interval and the same scale axis for the electric field shown

Which of the waves has the lowest frequency?

Q. The diagram shows a side view of the water waves, produced in a swimming pool by a wave machine. Identify the amplitude and the wavelength of the waves

Q228: Why is radioactive waste with half-lives of 10,000 years or longer more of a risk than waste with short half-lives, say ten years or less?

1. the initial activity will be much greater
2. the activity will not diminish much over thousands of years
3. the radiation is more likely to be alpha

Q229: Why are biofuels considered more environmentally friendly than fossil fuels?

1. biofuels can be replaced in a short time whereas fossil fuels need millions of years to form
2. biofuels do not release carbon dioxide when burned
3. biofuels use agricultural land which could be used for food production

Q230: A microwave cooker draws a current of 3 ampères when connected to 230 V a.c. mains. What power does it use?

Q231: Which of these types of electricity power plants can respond quickly to increased demand?

1. wind
2. nuclear
3. tides

Q232: A greenhouse uses a small 500 watt electric heater during the winter for 6 hours each night. How much energy does it use each week?

Q233: A diesel generator consumes 1 unit of fuel energy (1 kWh) every 10 minutes. What is its input power?

Q234: Calculate the cost of using a 5W energy-saving light bulb for 2 hours each day for 365 days if electricity cost 10p per unit

Q235: Which of these are secondary energy sources?

1. wind
2. solar
3. electricity

Q236: What is the correct sequence for the parts of a gas-fired power station?

Q237: What is the danger to life from ionising radiation?

1. cells can be destroyed
2. cancerous cells can develop
3. skin becomes charged

Q238: Here is a Sankey diagram for a coal-fired power station.

It shows that the efficiency of the boiler phase is 92% and the efficiency of the turbine and cooling phase is 51%.

Estimate the efficiency of the generator and transformer phase.

Q. Roughly how many galaxies are there?

Q. Refraction is the change in direction of a wave when it passes from one material to another.

Which of these statements is true?

1. this happens if the speed of the wave is different in the two materials
2. electromagnetic waves cannot be refracted
3. the wave will not change direction if it is travelling perpendicular to the boundary

Q. Which of these animals has the greatest and which has the least momentum?

1. a 200 kg tuna fish swimming at 5 m/s
2. a 80 kg lion running at 12 m/s
3. a 30 kg eagle flying at 30 m/s

Q. A curling stone is 20 kg. It is released at a speed of 4.5 m/s. It takes 25 seconds to stop. What is the friction force slowing it down?

Q. How many neutrons are there in an atom of the isotope denoted . .

Q. "Nuclear medicine uses radioactive tracers to find out what is wrong with a patient. 
Gamma emitting radioactive materials, with a short half-life, are used as tracers to 
examine blood flow in a patient’s body.
One tracer used is technetium-99 (Tc-99). It has a half-life of 6 hours. It only emits low 
energy gamma rays, which easily escape the body to be detected by gamma ray cameras. 
These cameras feed information to a computer which builds up a picture of the path taken by the tracer through the patient’s body.
Tc-99 can be given to a patient by mouth or by injection. It produces no discomfort and 
after a few days there is no sign that the test was ever done."

After reading this a patient asked for more reassurance. Which of the statements below is not correct?

Q245:. Thorium 230 decays to Radium 226 with a half-life of 250 000 years. Radium 226 decays to Radon with a half-life of 1600 years.

X is a nucleus of Thorium. Y is a nucleus of Radium produced 1000 years ago. Z is a nucleus of Radium produced today.

Which of these nuclei is most likely to decay next?

Q246:. Which of these is not electromagnetic radiation?

Q247: The skydiver is moving under the influence of two vertical forces. 

Air resistance is currently 850 newtons upwards

Weight is 750 newtons downwards

Which of these could describe the motion of the skydiver?

1. moving downwards at a decreasing speed
2. accelerating upwards
3. moving downwards at a steady speed

Q248: A plane is flying under the influence of 4 forces.

The plane is increasing its height but remaining at the same forward speed

Which of these statements is/are true?

1. force 1 must be greater than force 3
2. force 3 could be greater than force 1
3. force 3 and force 1 cannot be equal

Q249: Two charges, both positive are exerting forces on each other.

Which of these statements is/are true?

1. X experiences a force to the left
2. Y experiences a force to the left
3. the two forces are equal even if the charges are not the same size

Q250: Three charges are exerting forces on each other.

If the unmarked charge is negative, in which direction will it experience the force from the other two?

Q251: The power ratings of different parts of an electric cooker are shown below.

The mains voltage is 230 V.

Calculate the current needed if all three parts are on at the same time.

Q252: Which direction is the force on the YZ part of this coil?

Q253: A student has set up this circuit to measure the current through and the voltage across two components.

Setting the supply to several different voltages the student collects several pairs of readings. This graph is plotted

Estimate the resistance of the lamp (L) when the supply was set at 6.0 volts

Q254: A magnet is dropped through a coil. The logger records the induced voltage as shown

What differences would have been observed if the magnet was dropped from a higher point?

1. the peak voltage would have been lower
2. the pulse would have taken longer
3. the pulse would have been reversed

Q255: A 3000 kg barge floats at 0.5 m/s into a rubber fender, then bounces straight back at 0.3 m/s.

What is its momentum change?

Q256: Some astronomers are proposing to put a telescope on a satellite into a large planetary orbit following the path of Saturn. It is hoped this would improve parallax measurements to other stars in the Milky Way.

Which of these points below would be advantages of the Saturn orbit telescope compared with one on the Earth's surface?

1. The baseline for angle measurements would be much larger than the diameter of the Earth's orbit
2. The orbit time for Saturn is about 30 Earth years
3. There would be less scattering and light pollution away from the Earth's atmosphere

Q. The transmission of electromagnetic waves of different wavelengths through the atmosphere means that there are no earth bound telescopes using?

Q258: Which of these is NOT a form of electromagnetic radiation?

Q. Refraction is the change in direction of a wave when it passes from one material to another. The different materials could be

1. space to air (atmosphere)
2. air to glass
3. mantle to core

Q260: Which position is the Moon in if an eclipse of the Moon is likely?

Q261: A star that appears a certain brightness could be a very luminous star a great distance away or a not very luminous star which is quite close. Astronomers need a way to work out how luminous a star is.

Which of these true statements does not help to work out the luminosity or distance of a star

Q262: Type 1a supernovae are known as standard candles because 

Q263: This is a Hertzsprung-Russell diagram with the usual axes.

The positions of the Sun and four other stars are marked.

Which star(s) could be Main Sequence stars?

Q264: These equations show the reactions that take place when hydrogen nuclei fuse to form helium nuclei.

What is the product of the middle equation?

Q265: The diagram shows waves approaching a boundary (blue) which is tilted towards the direction of motion of the wavefront. 

The wave speed is less when it travels through the blue material.

Which of these statements about the waves when they pass into the blue material is/are true?

1. the direction changes towards Y
2. the frequency increases
3. the wavelength decreases

Q266: Which of these types of telescopes is only used from space?

Q267: Why is it essential to be able to use telescopes on different parts of the Earth?

Q268: In addition to a convex lens used as an eyepiece, which of the following could be used to make a telescope?

1. another convex lens
2. a concave mirror
3. a convex mirror

Q269: The great debate in 1920 was between Heber Doust Curtis and Harlow Shapely. It concerned the nebulae that had been observed and their relationship to the Milky Way.

Harlow Shapely claimed that the Milky Way was the only galaxy and that these nebulae were just clouds inside it

Heber Curtis claimed that these nebulae were other galaxies

What was the observation that settled this dispute?

Q270: Huge optical telescopes usually have a concave mirror rather than an objective lens. 

Which of the following are reasons for this?

1. large mirrors are easier to make accurately than large lenses
2. refraction splits light into different colours
3. the image needs to be the right way up

Q271: The distance between galaxies is typically 

Q272: Cepheid variable stars pulse in brightness, with a time period that depends on their . . . 

A student has two convex lenses. He is going to make an experimental telescope. Which of the lenses should be used as the eyepiece?

Q274: What physical quantity do astronomers measure to determine the recession speed of a galaxy, in order to estimate its distance away?

Q275: The graph shows the recession speed of a number of galaxies plotted against their distance away.

What value do these results give for the Hubble constant?

Q276: Which planet lies between Mercury and Earth?

Q277: The diagram shows the movements of several bodies in a planetary system.

What kind of body is object X?

Q278: A small rock is discovered orbiting the sun in a circular path with a period of 300 earth days. Between which two planets is it?

Q.

In the diagram you can see Saturn (S), Jupiter (J), Mars (M), Earth (E) and the Sun. All three planets are visible from Earth for a few hours at night. Which of these best describes the view?

Q.

The diagram shows Earth, Venus and Mercury at a particular time. The direction that Earth is spinning is also shown.

Which of these statements are true?

1. Venus is visible for a while before the Sun rises
2. Mercury is visible for a while after the Sun sets
3. Both Venus and Mercury are visible at midnight

Q281: Why are scientists interested in the spectrum of a star?

1. They can tell how hot it is from the wavelength of the peak intensity
2. They can detect all the elements in the core
3. They can work out what gases the light has passed through

Q282: A spaceship is to travel from the Earth to Jupiter. Jupiter is 5 times as far from the Sun as the Earth is. The scientists want to use solar panels to power the onboard electronics.

The power when it arrives near Jupiter, compared to the power near Earth will be . . .

Q. Vesta and Ceres are both large asteroids or dwarf planets. Which of the following true statements could explain why Vesta is visible to the naked eye but Ceres is not?

1. The orbit of Vesta is closer to the Sun
2. The speed of Vesta is greater
3. Ceres is much larger than Vesta

Q284: Which of these is/are dwarf planets?

1. Venus
2. Ceres
3. Pluto

Q285: Which of these characteristics of a body in the Solar System does NOT make it more likely that the object will be visible from Earth?

Q286: A Trojan is the name given to a small planet (or asteroid) that follows almost exactly the same orbit as a planet.  Jupiter has hundreds of these.  Why do they not collide with the planet whose orbit they share?

1. Their orbit times are the same as the planet's
2. They repel the planet
3. Their speed is the same as the planet's

Q287: Which of the following statements supports the idea that dinosaurs were wiped out by an asteroid collision?

1. A layer of material found in asteroids is found all over the world in rocks formed about the time the dinosaurs disappeared.
2. Fossils suggest the dinosaur numbers were decreasing for hundreds of thousands of years.
3. A large amount of dust thrown into the atmosphere could have caused the whole world to have a winter that lasted for hundreds of years.

Q288: Which of the following would not be found in the solar system?

Q289: The Moon has features which we can see when they are illuminated, but we only ever see the features on one half of the Moon. There are features which were never seen on the other half, until spacecraft went past the Moon. This is because . . .

Q290: Here is some data about planets

A potato-shaped rock is discovered with a circular orbit of the Sun that takes 480 Earth days to complete. Where does its orbit lie relative to the planets?

Q291: The vibrations detected from the site of an earthquake are called ______ ?

Q292: The diagram shows some tectonic plates and the direction they are moving. The darker shading shows continental crust and the lighter shade shows oceanic crust.  

In which places would you expect to develop (i) an under sea earthquake, and (ii) coastline mountains alongside a sea trench?

Q293: A soundwave travels at 340 m/s. What is the wavelength of a sound of frequency 2000 hz?

Q294: Following an earthquake, a P wave arrives at a detector 240 km away after a time of 40 seconds. The frequency of the P-wave is 20 hertz. What is its wavelength?

Q295: The diagram shows a seismic wave passing from the liquid core to the mantle.

Which of these statements is/are correct?

1. Y shows the refracted wave emerging from the core
2. It is an S--wave
3. The wave X travels faster than the wave Y

Q296: Which of the following is the name given to areas of low pressure in a sound wave?

Q297:. Which of these statements about sound is true?

1. a higher-pitched sound will have a lower frequency
2. sound cannot travel through a vacuum
3. sound waves are transverse

Q298: Roughly how many stars make up the Milky Way?

Q299: If the following are arranged in order of distance which one should be in the middle?

Q300: Which of these properties of a star is affected by how far away it is?

1. its apparent brightness
2. its mass
3. its luminosity

Q301: Here are some statements about the Milky Way.

Which is/are true?

1. The Sun is in one spiral arm
2. It is the largest known galaxy
3. Parts of it are visible from Earth without a telescope

Q302: Roughly how many galaxies are there?

Q. The speed of light is 300000 km/s. Which of these is a rough estimate of one light year in km?

Q304: Stars which are much more massive than the Sun

1. will be hotter
2. will have a shorter life
3. will convert more hydrogen to helium every second

Q. The graph shows the velocity of a bus in metres/second plotted against time in seconds. How far did the bus travel from the start of the journey until it reached A? (In the first 20 seconds).

Q306: The diagram shows 12 moving pucks. How many of them have the same speed as X?

(Do not count X in your answer)

Q. A 60kg water skier releases the rope while he is travelling at 12 m/s. What is his momentum?

Q. A curling stone is 18 kg. It is released at a speed of 2.0 m/s. The friction force slowing it down is 4 N. How long will it take to stop?

Q. A car has a mass of 800 kg. It is travelling at 12 m/s. Just ahead the traffic lights change to red. The car slows from 12 m/s to 0 m/s in 3 seconds.

Calculate the momentum change of the car and the size of the braking force.

Q310:. A car accelerates at 4 m/s² for 4 seconds. It then has a velocity of 44 m/s.

What was its velocity before it started accelerating?

Q311: A car is moving under the influence of two forces, the traction and the drag.

The car reaches its maximum speed of 45 m/s when the drag is 5000N.

Which of these statements is/are true?

1. the maximum traction force is 5000N
2. if the drag at 45m/s is decreased the maximum speed will be greater
3. the drag and the traction force are an interaction pair

Q312: Hadrian's Wall runs in an East-West direction. A scotsman (on the north side) leans against the north side of the wall with a force of 50 newtons.

Which of these statements is/are true?

1. the wall experiences a force of 50 N in the south direction
2. the scotsman experiences a force of 50 N in a north direction
3. the scotsman must be pushing the ground with a force of 50N in a north direction

Q. A skateboarder, weight 600 N, with board, rides down a slope from rest. The height of the slope is 5 metres. How much potential energy is changed into kinetic energy?

Q314: A pendulum swings from side to side with very little loss of energy.

The energy changes from potential (at the end of each swing) to kinetic (in the middle of each swing)

The bob on the pendulum in the diagram has a weight of 2 newtons.

The maximum kinetic energy of the bob is 0.08 joules

What height (h) does it reach at the end of a swing?

Q. Seven 12 volt 6 watt lamps are connected to a single 12 volt supply. What total current will be drawn from the 12 V supply?

Q316: Two charges, both positive, are exerting forces on each other.

Which of these statements is/are true?

1. X experiences a force to the left
2. like charges repel
3. if both charges were negative the two forces would be in the opposite directions

Q317: A circuit is connected with a battery and two resistors together with three voltmeters.

Which of these statements about the voltmeters is true?

1. V1 = V2 = V3
2. V1 = V2 + V3
3. V2 = V3

Q318: The bulb in this circuit is glowing.

Which of these statements could be true?

1. the current through the battery is the same as the current through the bulb
2. the voltage across the battery is the same as the voltage across the resistor
3. the current through the bulb is the same as the current through the resistor

Q. Which of these transformers will produce 23 V a.c. from a 230 V a.c. supply?

1. primary 1000 turns, secondary 100 turns
2. primary 5000 turns, secondary 500 turns
3. primary 450 turns, secondary 90 turns

Q320: A student has constructed an electric motor, as shown. 

She wishes to reverse the direction of rotation.

Which of these statements is/are true

1. reversing the battery connections will reverse direction
2. swapping the N and S poles of the magnet will reverse direction
3. the motor as pictured rotates clockwise

Q. Which direction is the magnetic field between the poles of this magnet?

Q322: The diagram shows an electromagnet

Which of these changes will make the electromagnet stronger?

1. put more turns on the coil
2. increase the voltage of the supply
3. put a soft iron core inside the coil

Q323: What is the most appropriate use for this diagram?

Q. A convex lens has a power of 4 dioptres. What is its focal length?

Q. Ed has a telescope with two convex lenses. X has a focal length of 120 cm. Y has a power of 25 dioptres.

Which of these statements are true?

1. X is the eyepiece
2. the magnification is 30 times
3. the telescope is about 80 cm long

Q. Jeff has two convex lenses and wants to use them to make a telescope to look at a distant ship. X has a focal length of 12 cm and Y has a focal length of 60 cm. Which of the following pieces of advice should be considered?

1. X should be the objective lens
2. the image will be upside down
3. the two lenses should be mounted about 70 - 75 cm apart

Q. The Hipparcus telescope has been used to measure the parallax angle for some nearby stars.

Which of these stars listed is the closest?

The parallax angle is measured in seconds of arc

Q. The parallax angle for 61 Cygni A has been measured as 0.287 arcseconds. Estimate its distance in parsecs

Q. Why is a large aperture on a telescope an advantage

1. to collect more energy from the signal
2. to minimise the spreading effect of diffraction
3. to get greater magnification

Q330: The table shows the celestial coordinates (right ascension and declination) of four of the brightest stars. 

Which of these pairs of stars are likely to be visible at the same time?

Q331: Which position is the Moon in if a solar eclipse is likely?

Q332: Who found a relationship between the speed of recession of a galaxy and its distance away?

Q. Which of these temperatures is the coldest?

Q. How would the Kinetic Theory of Gases explain the pressure of a gas increasing when its temperature is increased?

1. The molecules speed up
2. The molecules hit the walls harder
3. The molecules hit the walls more often

Q. In a plasma of hydrogen ions, fusion of the hydrogen ions can occur when when the ions can get close enough together to overcome the repelling forces. This is most likely to happen if . . . 

Q. Calculate the final temperature of a cylinder of gas that is heated from 27 celsius but not allowed to expand. The pressure increased from 15 Pa to 20 Pa.

Q337: This is a Hertzsprung-Russell diagram with the usual axes.

The positions of the Sun and four other stars are marked.

Which star could be a White Dwarf?

Q338: This is a Hertzsprung-Russell diagram with the usual axes.

The positions of the Sun and four other stars are marked.

Which star is the most likely to be the next to go supernova?

Q. What is the name for a packet of radiation?

Q. Which of these is a process by which radiation can damage cells?

1. fusion
2. burning
3. ionisation

Q. Which electromagnetic radiation has all of these

• a wavelength longer than ultra violet
• photons with less energy than infra red
• a frequency higher than radio waves

Q. A professor has set up a matt black plate so that the Sun's rays fall directly on it. He measures the rising temperature of the plate every minute. Which of these statements is/are true?

1. the plate is an excellent absorber of radiation
2. the plate itself will radiate more and more the hotter it gets
3. when the plate is radiating as much as it receives from the Sun, it has reached its maximum temperature

Q.

A geostationary satellite is in orbit 36 000 km above the Earth's surface. A signal is transmitted from X to Y by first being transmitted to the satellite, then, not reflected, but retransmitted to Y.  Which of the following statements about this process are not true?

Q344: Which kind of electromagnetic wave can have a wavelength greater than 10 metres?

Q345: Which of the following is NOT a property of electromagnetic waves?

Q. Which of these steps would help to reduce the Greenhouse Effect?

Q. Which of the following are consequences of increased sea temperatures

1. Raised sea levels
2. Loss of ozone layer
3. Melting ice caps

Q. Which of these statements is/are true?

1. the atmosphere absorbs some em radiation
2. the atmosphere reflects some em radiation
3. the atmosphere transmits some em radiation

Q349: Which of these protects human skin from ultra-violet radiation?

1. clothing
2. sun-screen
3. ozone

Q350: Which of these electromagnetic waves passes through the atmosphere with least energy loss?

Q351: Which kind of electromagnetic wave can bounce off the ionosphere?

Q. Which of these is not an advantage of digital signals?

Q. To boil enough tapwater for a particular teapot requires 250 000 joules. How long will it take a kettle to do this if it is rated at 2.0kW?

Q. For how long can a 5W bulb be on for before it uses one unit of electrical energy?

Q. An electric iron is rated 920 watts. What current does it draw from a 230 V supply?

Q356: When fully charged, a rechargeable 2.0 volt battery supplies a current of 0.5 ampères for 20 minutes before it needs recharging.

How much energy does this battery hold?

Q357: Diesel fuel holds 36 MJ of energy per litre.  A diesel generator produces 9 MJ of electrical energy for each litre of fuel used. What is its efficiency?

Q358: Here is a Sankey diagram for a coal-fired power station. Calculate the useful electrical power output from 100MW input.

Q. Electricity can be generated from many energy sources. Which of these sources does not use a turbine?

Q. Electricity can be generated from many energy sources. Which of these sources are renewable?

1. geothermal
2. gas
3. waves

Q. Which of the following forms of renewable energy is most reliable

Q362:. Here are five energy sources:

1. gas
2. hydro-electric
3. nuclear
4. oil
5. wave

Which two are renewable?

Q363:. A site has become available for a new power station. In the process of deciding which energy source (gas, oil, coal, nuclear) is the cheapest, which of the following would not be a determinant?

Q364: Which type of power station can respond most efficiently (wasting least energy from the primary source) to a drop in demand?

Q. The diagram below shows atoms of two isotopes of the same element.

What are W, X, Y and Z?

Q. Uranium 238  decays to thorium 234 which then decays to protactinium 234.

What radiation will be emitted?

Q. What happens to the activity of a radioactive gas if it is heated?

Q. The activity of a radioactive sample is 280 Bq. 72 hours later the activity has fallen to 70 Bq. What is the half-life of this source?

Q. How many neutrons are there in the nucleus of an isotope denoted 

Q. The table below shows information about different nuclei involved in the process of nuclear 
fission. 

A nucleus of plutonium undergoes fission when bombarded with a slow moving 
 neutron (n) splitting into the daughter nuclei yttrium and caesium.

How many neutrons are released during this fission process?

Q. How many protons are there in an atom of the isotope denoted . .

Q372:. Thorium 230 decays to Radium 226 with a half-life of 250 000 years. Radium 226 decays to Radon 222 with a half-life of 1600 years. Radon 222 decays to Pollonium 218 with a half-life of 3.8 days

Nucleus X is Thorium, nucleus Y is Radium, Nucleus Z is Radon

Which of these statements is NOT true?

Q373: A radioactive source is fixed in a vacuum, 50 cm away from a detector.

A number of different shields are inserted in succession:thin paper, thin foil, lead plate 4 cm thick

The table gives the count rate

What is the most likely radiation emitted by the source?

Q374: The half-life of a particular isotope is 50 minutes.

At one time the activity of a sample of this isotope is 120 units.

What would you expect its activity to be after just 25 minutes?

Q. A freshly prepared sample of pure Radon-220 has been obtained

Radon-220 is unstable and decays into Polonium-216 with a half-life of 56 seconds

Polonium-216 is also unstable and decays into Lead-212 with a half-life of 0.15 seconds

Which of these statements is/are true?

1. a particular radon nucleus is likely to decay before a particular polonium nucleus
2. less than 0.1% of the radon will remain after one hour
3. both decays release beta radiation

Q. Which model offers a reasonable explanation for the process of beta decay?

Q377: In a famous scattering experiment alpha particles were directed at a thin piece of gold foil.

At the time the atom was seen as ball of positively charged, massy material with electrons embedded in it, like currants in a bun.

This view changed because because of the results of the experiment. The new model said . . . . . 

1. most of an atom is empty space
2. all of the positive charge is confined to a tiny nucleus
3. almost all of the mass is confined to a tiny nucleus

Q378: A sample of a radioactive isotope has an activity of 160 units. Two hours later the activity is 20 units.

What is the half-life?

Q. A nuclear reactor includes a moderator (e.g. graphite), control rods (e.g. boron), fuel rods (e.g. uranium) and a container (e.g. steel and concrete).

Which of these statements is correct?

1. the purpose of the moderator is to absorb neutrons
2. the purpose of the control rods is to slow down the neutrons
3. the purpose of the fuel rods is to provide the fissionable atoms

Q. Which of the following is a NOT a source of background radiation?

Q. Radioiodine (Iodine - 131) decays to Xenon by emitting a beta particle and a gamma ray.

Which of these statements is/are true?

1. the xenon isotope has a mass number of 130
2. the xenon isotope has the same proton number as iodine
3. the radiation produced will not go further than a few centimetres in air

Q. Which of the following is not a reason for using computer-controlled telescopes?

Q. Which of the following is a reason for operating a telescope from the Earth rather than from space?

Q. Which of the following are disadvantages for a possible site for an major observatory?

1. a region of high altitude
2. a region of low rainfall
3. an area with good transport links

Q. Which of the following are advantages of a optical space telescope over an optical land-based telescope?

1. access for repairs
2. refraction by the gases in the atmosphere
3. cost to set up

Q386: The diagram shows the sun, the earth and three different positions of the moon 1, 2 and 3. In which of those positions will the moon appear like the lower picture?

Q387: Which of these statements about the sun is/are true?

1. The proportion of hydrogen is increasing
2. The proportion of helium is increasing
3. A process of nuclear fusion is taking place

Q388: Which of these phenomena is the Moon responsible for?

Q. Which of these explains why the Sun and the Moon appear to be approximately the same size​

1. The Moon's orbit has a radius of approximately 100 Moon diameters
2. The Moon only reflects light from the Sun
3. The Earth's orbit has a radius of approximately 100 Sun diameters

Q. The radius of the Moon's orbit around the Earth varies between 363 000 km and 406 000 km. This means that 

1. the orbit of the Moon is not circular, with Earth at centre
2. the Moon seems bigger when it is low on the horizon
3. the moon appears larger and smaller during an orbit

Q391:. Why is it warmer in Europe in the Summer?

1. the Sun is nearer
2. the atmosphere has more carbon dioxide
3. the Sun is more directly overhead

Q392:. What do moons orbit?

Q393: The Earth spins on its axis which is tilted 23 degrees away from a perpendicular to the plane of its orbit around the sun. This tilt is responsible for

1. Night and day
2. Summer and winter
3. Eclipses

Q394: The intensity of light from the sun is much greater near the equator than near the poles. This is because near the equator the sun is often . . .

Q395: Which of these is the source of the Suns energy?

Q396: To make a scale model of the Earth and the Sun a teacher uses a football (diameter = 0.3 m) to represent the Sun. What could she use to represent the Earth? She has a peppercorn (diameter = 0.3 cm) a marble (1.5 cm) and a golf ball (3 cm)

Q397: When the Moon is new we can see hardly any of it. Why is that?

1. The Sun is at its weakest.
2. The near side of the Moon is not illuminated
3. The Earth casts a shadow on the Moon

Q398: Which of these diameters is the middle one when arranged in order of size?

Q. Some planets are much more likely to be visible than others. Which of these is a possible explanation of why a particular planet appears bright?

1. It is a large planet so reflects a lot of the sun's light
2. It is near the Earth so we see more of the light it reflects
3. It is near the Sun so receives a lot of light to reflect

Q400: Here is some data about planets

The entry for Distance under Earth is 150. What does that mean?

Q401: Here is some data about planets

The entry for Time is 1.9 for Mars. What does that mean?

Q402: Which of the following is a terrestial planet?

Q403: Earth's orbit is almost circular, with a radius of 150 million kilometres. The orbit of Jupiter has a radius of 780 million kilometres. What is the closest Earth gets to Jupiter and what is the greatest distance between them?

Q404: How many planets are there in the Solar System? (not including minor planets or dwarf planets)

Q405: What is meant by a planet's year?

Q406: The orbit of a comet is usually very elliptical. The Sun is not at the centre but at one of the two points called foci. The diagram shows a comet during its orbit. Which of the arrows shows approximately the direction of the main force on the comet?

Q407: Which of the following is the most likely origin of a meteoroid?

Q408: Here are three statements about meteoroids. Which of them uses the emphasized terms correctly?

1. An asteroid can be deflected from its orbit, and approach the Earth as a meteoroid.
2. You can see meteorites in some museums.
3. Meteors are visible because of the heat produced as they move through the atmosphere.

Q409:. Asteroids are composed of 

Q410: Which of these is likely to be the hottest?

Halley's comet is visible to the naked eye for a few months every 76 years. Which of these explanations is not true?

The vast majority of asteroids . . . ?

To sustain Earth-like animal life, a planet needs  . . . ?

1. to have at least one moon
2. to be close enough to its star to get to a suitable temperature
3. an atmosphere to absorb harmful radiation

Q414: Which of the following statements about comets is NOT true?

Q415: Here are three statements about meteoroids. Which of them uses the emphasized terms correctly?

1. Sometimes a meteorite will approach the Earth at a grazing angle and 'bounce' back into space.
2. You can see meteors in some museums.
3. There are many meteors travelling through space.

Q416: Place the following in order of mass, starting with the smallest

Q417: Which of these statements about comets is/are true?

1. Each time a comet passes near the Sun it loses some of its mass
2. Comets have orbits that reach the outer planets
3. The composition of a comet is different from the composition of an asteroid

Q418: The distance between stars B and C is measured every June and December. They always appear closer together in December.

What is the best explanation for this observation?

Q419: Which of these procedures is used to measure the distance to a star?

1. movements against the other stars over a year
2. timing radio waves travelling from the star
3. compare brightness with that of similar stars

Q420: There are two main methods for measuring the distance to a star, parallax and brightness measurements.

Which of these statements about this is/are true?

1. the parallax method is least accurate for a nearby star
2. the brightness method is most accurate when the star is of a particular type
3. Cepheid variable stars can act as ‘Standard Candles’

Q421: An arcsecond is 

Q. Arrange these distances in order from the smallest to the largest

1. 5 light years
2. 100 million km
3. 10 Astronomical Units (AU)

Q423: Which of these is a method for measuring distances to stars outside the Solar Syatem?

Q. Which of these distances is more conveniently expressed in light years than in km or astronomical units?

Q425: An astronomer measures the distance to an object in space as about 100 light-years.
The distance from the Sun to the nearest neighbouring star is about 4 light-years.
Which statement best describes the position of the object?

 

Q426: Astronomers measured the parallax angle for a star as 1/10000 of a degree. For a second star they measured the parallax angle as 1/100000 of a degree.

Which of these statements is true?

1. The first measurement needed the more sensitive instrument
2. The second star is further away
3. One star is much smaller than the other

Q427: What was the Sun formed from?

Q. Which of these statements about the sun is/are true?

1. The proportion of helium is decreasing
2. A process of nuclear fission is taking place
3. The proportion of hydrogen is decreasing

Q429: What are the two most abundant elements in the Sun now?

Q430: How is it thought the planets were formed?

Q431: What are the missing words in this description?

During the formation of the Sun, gas and dust clustered together under the influence of (1) _________ .  The attraction formed a bigger and bigger mass pulling more and more of the cloud. The pressure and temperature inside this mass (2) _________ .  Eventually the pressure and temperature in the core was sufficient so that hydrogen nuclei could (3) _______ together.

Q. Only very light elements were formed in the big bang.
Where are heavy elements like nickel and iron formed?

Q433: A star in that stage of its life in which it is still converting hydrogen to helium in its core is known as a Main Sequence star.

Which of these factors will make this stage shorter?

1. a smaller mass
2. a larger mass
3. a greater distance from other stars

Q434: Approximately how old is the Sun?

Q435: Which words complete the following sentences about stars?

We can only see stars because they give out _____

People in cities find it hard to see stars because of light _____

Astronomers have found that some stars have ______ in orbit around them

The words are not necessarily in the right order.

Q436:. Comparing two main sequence stars, X and Y, both about 100 light years from the Sun. If X is much hotter than Y then what other differences can you expect?

1. X will have a longer life as a Main Sequence star
2. Y will be brighter
3. X has a greater mass

Q437: There can be differences in the appearance of main sequence stars because

1. some are much hotter than others
2. some are nearer than others
3. some are fusing carbon

Q438: Which of these is the source of the Sun's energy?

Q439: The term 'Main Sequence' refers to 

1. A type of star that is fusing hydrogen into helium in its core
2. That period in a typical star's life in which it is stable
3. A collection of stars arranged in order of diameter

Q440: How many stars are there in the Milky Way?

Q441: In order to estimate how many galaxies there are, the Hubble telescope was directed at a small area of the sky in which there appeared to be no galaxies - (The tiny diamond shape - XDF - in the diagram below).

Using an exposure of 23 days however, several galaxies were visible.

The number of galaxies counted was 5500

The number of those diamond shapes which would fill the whole sky was 32 million

The best estimate for the number of galaxies is:

Q442: Here are some statements about the Milky Way.

Which is/are true?

1. The Sun is at the centre
2. It is rotating
3. It has a spiral shape

Q443: What does The Local Group refer to?

Q444: What is the name of our galaxy?

Q446: What happens to pieces of rock as they are transported by a river?

Q447: How can sedimentary rocks be found at the top of mountains?

Q448: The Grand Canyon formed because . .

Q449: What stops continents being worn down to sea level by erosion?

Q450:. Mountains are worn down by a process known as . . . . 

Q451:. What is the name of Wegener's theory of the movement of large chunks of the Earth's crust?

Q452: Name the process that wears mountains down.

Q453: Rocks get smaller because of weathering and erosion. The particles that are washed away get deposited at the bottom of lakes and the seas. The pressure builds up and the particles get compacted together. The water gets pushed out and crystals of different salts form, cementing the particles together. New rock is created but it is under water. This new rock is called . . .

Q454: Where are the oldest layers of rock usually found in a cliff made from sedimentary rock?

Q455: Which of the following processes is involved in the rock cycle?

1. Erosion
2. Sedimentation
3. Weathering

Q456: Which of the following observations did Wegener try to explain?

1. The similarity in the coastlines of South Africa and South America
2. The similarity in plants and animals in South Africa and South America
3. The existence of fossils

Q457: Which of the following was used to argue against Wegener's theory of Continental Drift?

1. There are very few animals common to South Africa and South America
2. No movement of the continents can be detected
3. The effect of the tides is too small to explain the movement of continents

Q458: What was the conclusive evidence for the theories of Continental Drift and Tectonic Plates?

Q459: Which of these was NOT part of the evidence Wegener was able to use to back up his theory?

Q460: Identify South America and South Africa on this map

Q461: Wegener presented his theory of continental drift for Peer Review. What is Peer Review?

Q462: How does continental drift account for mountain building?

1. Weathering wears away the softer rock leaving hard lumps behind
2. The surface of the Earth wrinkles as it cools
3. Continents push against each other forcing rock upwards

Q463: Fossils of sea creatures have been found high in the Swiss Alps.  Why was that difficult to explain without the theory of Continental Drift

1. The Alps are far from the sea
2. Fossils were formed millions of years ago
3. The Alps are high above sea level

Q464: Which of the following is not thought to be caused by moving tectonic plates?

Q465: The outer layer of the Earth consists of _____ ?

Q466: The diagram shows the pattern of magnetism in the rock under the Atlantic ocean. The dark areas have a N-S field (positive) and the light areas have a S_N field (negative).

Which stripe of rock would you expect to have a similar age to positive stripe M?

Q467: This question is about seafloor spreading.

The diagram shows the magnetic patterns that appear in the seafloor near mid-ocean ridges. These patterns were first found in the 1950s.

1. Every few thousand years the direction of the Earth's magnetic field changes
2. the plates underneath are separating slowly
3. As the magma solidifies into rock it 'freezes-in' the Earth's magnetic field direction

Q. What were the main source(s) of heat inside the Earth?

1. Energy from collisions
2. Radioactive decay
3. Nuclear fusion

Q469: What causes convection currents in the more fluid parts of the mantle?

Q470: Which of these is the order for the layers inside the Earth, starting at the centre?

Q471: Approximately how fast are tectonic plates moving each year?

Q472: Where are the sites of volcanoes and earthquakes most likely?

Q473: Which of these observations can be explained by the idea of moving tectonic plates?

1. Mountains exist, very often in chains or ranges
2. Volcanoes and earthquakes are much more common in some places than others
3. Rock features wear away over long periods of time

Q474: The diagram shows some tectonic plates and the direction they are moving. The darker shading shows continental crust and the lighter shade shows oceanic crust.  

In which places would you expect to develop (i) a mid ocean ridge, and (ii) rising mountains?

Q475: Which of the following explains convection currents in the more fluid parts of the mantle?

1. Parts of the mantle are heated more than other parts
2. Mantle is less dense when heated
3. Less dense mantle rises and denser mantle sinks

Q. What were the main source(s) of heat inside the Earth?

1. Effects of gravity and friction
2. Radioactive decay
3. From the heat in the Protostar

Q477: A tuning fork is vibrating. A music student can identify the note that it makes.

1. Sound waves travel from the fork to the student's ears
2. The air molecules move from the fork to the student's ears
3. The air molecules move forwards and backwards passing on the vibrations

Q478:. Which of these statements about sound is true?

1. a higher-pitched sound will have a shorter wavelength
2. sound waves are longitudinal
3. sound waves can travel in a vacuum

Q479: The diagram shows a wave being produced on a slinky. The distance from the compression to the rarefaction is 0.3 metres. Which of these statements apply?

Q480: A longitudinal wave travels along a slinky spring. Jeff observes a spot of paint on the slinky. It moves back 10 cm then forward 10 cm back to where it started, three times a second.

What can be concluded from these observations?

Q. Which of these is a type of longitudinal wave?

Q482: Which of the following properties is the same for all waves in the electromagnetic spectrum?

Q483: What is the speed of a ripple if it has a wavelength of 2 cm and a frequency of 10 hertz?

Q484: A soundwave travels at 340 m/s. What is the wavelength of a sound of frequency 1000 hz?

Q485: What is the unit of frequency?

Q486: Darth holds one end of a taut rubber cord. The other end is tied to a hook 30 metres away. Darth moves his end rapidly from side to side making five complete left-right movements in one second. Han takes a photograph of the waves moving along the cord. It takes 3 seconds before the wave reaches the other end. Which statements is/are true?

1. This is a transverse wave
2. This is a longitudinal wave
3. The wavelength is 10 metres

Q487: What property of waves is measured in hertz?

Q488: The diagram shows ripples expanding from a vibrating dipper on the surface of water.

Which of the following is/are reduced at point Y compared to point X?

1. the wavelength
2. the speed
3. the amplitude

Q. Four wave patterns of radiowaves from a star are shown below. Each graph shows the same time interval and the same scale axis for the electric field shown

Which of the waves has the largest amplitude?

Q490: Which of these is not a measure of the wavelength of a radio wave?

Q491: Bobby has kicked his ball into the middle of a pond.
The ball is 10 m from the edge of the pond.
He tries to move the ball by making waves on the water with a stick.
Bobby hits the edge of the pond with the stick. He makes 6 complete waves in 12 seconds.
He counts exactly 4 complete waves between his stick and the ball.
The waves are all equal.

What is the speed of Bobby's wave?

Q492: Albert holds one end of a long stretched slinky and begins to move it quickly forwards and backwards. Jeff videos the slinky and analyses the movie. He counts four compressions and four rarefactions passing a point in 2.0 seconds. He measures the distance between a compression and a rarefaction and finds it to be 0.6 metres.

Which of these is a correct calculation of the speed of the compression wave in the order: wavelength, frequency, speed

Q493: The diagram shows a side view of the water waves produced by a wave machine in a swimming pool.

What are the amplitude and wavelength of these waves?

Q494: What kind of wave reaches a seismograph first?

Q495: The diagram shows a seismic wave X striking a boundary between two parts of the inner Earth.

Which of these statements is/are correct?

1. Y is a reflected wave
2. one of the waves is refracted
3. Y is faster than X

Q496: The diagram shows a seismic wave X striking a boundary between two parts of the inner Earth.

Which of these statements is/are correct?

1. Y is a reflected wave
2. one of the waves is refacted
3. Y is faster than X

Q497:. The diagram shows points on the surface of the Earth where P and S waves have been detected following an earthquake at X

Which of these ideas helps to explain what is happening?

1. P waves can pass through liquids and solids
2. S waves can pass through solids only
3. Part of the Earth's core is liquid

Q498:. Earthquake waves travel through the Earth from A to B and from A to C.

Which of these statements is/are true?

1. at B, P-waves are detected before S-waves
2. P-wave vibrations are perpendicular to the direction the wavefront is moving
3. P-waves cannot be detected at C

Q. Refraction is the change in direction of a wave when it passes from one material to another. The diagram shows a wave passing from material X into material Y.

What can be said about this wave?

1. the speed of the wave is faster in X
2. the speed of the wave is faster in Y
3. the wave must be transverse

Q500: Refraction can cause waves to change direction.

On the left a wave passes from one material, X, to another, Y. The direction changes suddenly.

On the right is a wave following a curved path.

Which of these is/are true?

1. the speed in X is greater than the speed in Y
2. the speed of the curved wave is changing gradually as it travels from P to Q to R
3. the curved wave could be an S-wave in the mantle

Q501: Which of the following are properties of the seismic waves known as P-waves?

Q. An P-wave travels in a straight line to a detector 320 km from the epicentre of the earthquake, arriving after 50 seconds. What is the speed of the P-wave?

Q503: The diagram shows a seismic wave X striking a boundary between two parts of the inner Earth.

Which of these statements is/are correct?

1. Y and Z are both reflected waves
2. Y and Z are both refracted waves
3. Z is faster than Y

Q504: How do scientists know so much about very distant stars?

Q505: We know the universe is expanding because

Q506: Why is looking a distant stars like looking back in time?

Q507:. We can look at the light from a star divided up into each wavelength. Some stars appear to have slightly different spectra, with all the wavelengths longer than would be expected for that type of star.. What is this phenomenon called?

Q. The phenomenon of Red Shift can be detected in the radiation from most galaxies. Which of these statements is/are true

1. Only red light is affected
2. The greater the red shift the faster the galaxy is moving away
3. When red shift occurs the wavelength of all radiation appears longer than that which would otherwise be expected

Q. What is the average speed of the train that goes from Hastings to Rye in 18 minutes, a distance of 12 miles?

Q. A sprinter takes 3 seconds to get to a speed of 9 m/s. What is her acceleration?

Q. The graph of the height of a ball thrown up from a window shows a peak.

What is the velocity of the ball at that peak?

Q. The graph shows the thinking distance and the braking distance for a car travelling at different speeds.

 Look at the thinking distance for a speed of 25 m/s.How long is it expected to take for a driver to react to a danger and start braking?

Q. The diagram shows 12 moving pucks. How many of them have the same velocity as X?

(Do not include X)

Q514: The diagram shows three motion graphs.

Which of these statements is/are true?

Q. A displacement-time graph shows that an object moved from a position 11 metres north to a position 39 metres south in 5 seconds.

What was the average velocity?

Q. This velocity-time graph shows that an object reached a speed of 5 m/s after 5 seconds

What was the acceleration between t=2 seconds and t = 4 seconds?

Q. This velocity-time graph shows that an object reached a speed of 3 m/s after 2 seconds then continued at a steady speed before slowing down.

What was the acceleration between t=4 seconds and t = 5 seconds?

Q518: A car is moving at a steady speed of 25 m/s when the driver notices a stag in the road. It takes the driver 0.5 seconds to react and press the brake pedal. .

What is the 'thinking distance' ?

Q. The graph shows the thinking distance and the braking distance for a car travelling at different speeds. 

What distance would be required for a car travelling at 25 m/s to stop?

Q520:. A car accelerates at 2.5 m/s² for 6 seconds. It then has a velocity of 40 m/s.

What was its velocity before it started accelerating?

Q521: A small firework is launched vertically. This graph shows the height of the rocket at any time. 

The rocket explodes at time Z

When does the maximum speed occur?

Q. A coastguard measures the motion of a speed boat by timing it as it passes two buoys, 120 metres apart.

The stopwatch shows 2.4 seconds

He cannot tell if the boat followed a straight line.

Which of the following can be confidently concluded?

Q. What is the average velocity of a gull that flies from a yacht to a nest on a cliff, 300 metres away, due south, in 15 seconds?

Q. This displacement-time graph shows that an object moved 50 metres in 5 seconds.

What was the maximum velocity?

Q. This velocity-time graph shows that an object reached a speed of 3 m/s after 2 seconds then continued at a steady speed before slowing down.

What was the final displacement from the start position?

Q. A bus starts from rest with steady acceleration.

Of the graphs shown, which is likely to be the distance-time graph and which is likely to be the velocity-time graph?

Q. A 100 kg boat is drifting towards a quay at 2 m/s. What steady force will bring it to rest in 0.2 seconds?

Q. Which of these types of electromagnetic radiation has a wavelength that is shorter than that of ultraviolet waves?

Q. Which kind of radiation below carries the least energy in a photon?

Q. Photons of which of these types of radiation carry the most energy?

Q. What kind of radiation is used in conventional ovens?

Q. Which of these devices uses X-rays?

Q. Which is the fastest electromagnetic wave in a vacuum?

Q. A beam of radio waves contains two different wavelengths. One is 3m and has a frequency of 100 MHz. The other has a wavelength of 15m. What is its frequency?

Q. Microwaves heat food because . . .?

Q536:. What is meant by the intensity of a beam of radiation?

Q537: Infra-red radiation is transmitted, reflected and absorbed by glass as shown in the diagram.

What proportion of the infra-red is absorbed?

Q. Which of the following is not a type of ionising radiation?

Q. A beam of microwave radiation contains two different wavelengths. One has a frequency of 500 MHz and a wavelength of 0.6 metres. The other has a frequency of 1000 MHz. What is its wavelength?

Q. In order to be detected at a distance from a source, the energy from radiation has to be ?

1. reflected
2. transmitted
3. absorbed

Q.Which of these is/are possible sequences for a wave to travel from source to detector ?

1. transmission » absorption
2. emission » transmission » absorption
3. emission » transmission » reflection  » transmission » absorption

Q.The intensity of a radio signal in all directions is 0.24 watts per square metre at a distance of 1 km. What would its intensity be at a distance of 500 metres?

Q. Which of these colours of visible light has the highest frequency?

Q. Which electromagnetic radiation has both

• a wavelength longer than ultra violet
• photons with more energy than infra-red

Q. Which of the following is not a greenhouse gas?

Q. Which of these processes decreases the amount of carbon in the atmosphere?

Q. Which type of radiation is most affected by ozone in the atmosphere?

Q. Which of the following are consequences of increased sea temperatures

1. Melting ice caps
2. Raised sea levels
3. More hurricanes

Q. The average annual temperature has risen recently. What is the name of this effect?

Q. The ozone layer is important for our health and safety. Why is this?

Q551: 75% of the atmosphere is within what height above sea level?

Q552: Which of these statements about the  atmosphere is/are true?

1. the atmosphere absorbs some em radiation
2. the atmosphere reflects some em radiation
3. the atmosphere transmits some em radiation

Q553: What does a greenhouse gas do?

Q554: Why is the greenhouse effect bigger on Venus than on the Earth?

Q. Which gas in the atmosphere is best at absorbing ultraviolet radiation?

Q. The graph shows the variations in average temperature and the concentration of carbon dioxide in the atmosphere over the last 250000 years. Clearly there is a strong correlation between the average temperature and the concentration of carbon dioxide in the atmosphere.

It is unlikely to be a coincidence but we cannot tell whether the increase in temperature has caused the increase in the carbon dioxide concentration or if the increase in the carbon dioxide concentration has caused the increase in temperature or if there is a third change that has caused both effects. Which of the following helps to work out cause and effect?

1. A computer model of the Earth's climate
2. A wax model of the Earth's surface
3. Experiments on the absorption of different radiations by different gases

Q. What does the S stand for in SPF factor?

Q. Global warming can cause more extreme weather because . . .?

Q559: Which of these protects human skin from ultra-violet radiation?

1. clothing
2. sun-screen
3. ozone

Q560: Which of these activities increases the amount of carbon dioxide in the atmosphere?

1. burning fossil fuels
2. mining for precious metals
3. clearing forests to make settlements

Q561: Which of the following is NOT a projected consequence of Global Warming?

Q. A loose railway carriage (4000 kg) is rolling into buffers at 3m/s. How long will the collision take if the force is to be exactly 10000N?

Q. A small jet, mass 2000 kg, lands at 60 m/s. Its engine can provide a reverse thrust of 3000N.

For how long should the reverse thrust be applied to bring it to rest?

Q. A 900 kg car has brakes which exert a force of 1500 newtons? How long will it take the car to stop from a speed of 20 m/s

Q. Four objects of different masses are moving at different speeds

1. 8 kg moving at 5 m/s
2. 12 kg moving at 4 m/s
3. 15 kg moving at 3 m/s
4. 25 kg moving at 2 m/s

Which one has the greatest momentum?

Q566: A 100 kg spacecraft needs to increase its speed from 2000 m/s to 2200 m/s in 5 seconds.

What thrust (force) will be needed to do this?

Q567: Heber and Harlow both have a mass of 80 kg.

They jump off a wall. Just before each lands he is moving at 8 m/s

Heber lands with stiff knees and stops in just 0.1 seconds

Harlow bends his knees as he lands and stops in 0.4 seconds

What are the impact forces?

Q568: What is the momentum of a 0.2 kg salmon swimming at 8 m/s?

Q569: A 100 kg rowing boat floats at 1.5 m/s into a rubber fender, then bounces straight back at 0.5 m/s.

What is its momentum change?

Q. A curling stone is 20 kg. It is released at a speed of 2.5 m/s. What is its momentum?

Q. A skateboarder, mass 75kg, is skating along the flat at 4m/s and continues up a slope until he comes to a halt. What kinetic energy did he have on the horizontal section?

Q. A roller coaster is lifted up the first incline by a chain but then runs almost frictionlessly down and up slopes. Here is the track. At which points X, Y and Z will it have the greatest speed and the least speed?

Q. A car of mass 2000 kg, travelling at 8 m/s has its speed reduced to 5 m/s when it goes through 5 metres of sand in the road. How much kinetic energy has the car lost?

Q. Four objects of different masses are moving at different speeds

1. 8 kg moving at 5 m/s
2. 12 kg moving at 4 m/s
3. 15 kg moving at 3 m/s
4. 25 kg moving at 2 m/s

Which one has the greatest kinetic energy?

Q575: Chuck Morris claims to have pushed a tank 100 metres with the tracks locked. The force required to do that is 100 MN

How much work did he do?

Q576: A husky pulls a sled up a slope using a force of 180 newtons

The sled moves 3 metres.

How much work did the husky do?

Q577: An electric canon fires a ball with a kinetic energy of 6000 joules

The force that fires the canon is 10000 newtons and it acts along the full length of the barrel.

What is the length of the barrel?

Q578: How much gravitational potential energy does an iron ball (weight = 50 newtons) have when it has been raised 5 metres?

Q579: The rollercoaster train has a weight of 5 kN

How much gravitational potential energy is transformed between the highest point (140 m) and the first dip (50 m)?

Q. A steady friction force slows a  trolley with 72 joules of kinetic energy to a standstill in a distance of 18 metres. What is the friction force?

Q. A forklift truck raises a load of 150 newtons onto a platform 2 metres high.

How much work has the truck done on the load?

Q582: A wagon on a toy roller coaster has a mass of 0.4 kg? At the top of the slope it has 20 joules of gravitational potential energy.

How fast is it moving at the bottom of the slope? (You can assume there is no friction)

Q583: Which of these will appear to move relative to the background of stars over a few weeks?

Q584: On a star map the ecliptic shows as a line with a wave in it. What follows the path of the ecliptic exactly?

Q585: A photograph of a particular star recorded with a long exposure shows an arc rather than a point. If the arc is a quarter circle exactly, what was the time of the exposure?

Q586: The table shows the celestial coordinates (right ascension and declination) of four of the brightest stars. 

Which of these follows a path closest to the celestial equator?

Q587: Which position is the Moon in when it is new?

Q588: What is it called when a planet appears to move off its normal course in the sky and make a loop before continuing?

Q589: What is a solar day?

Q590: The diagram shows a band of stars with declination between +40 degrees and -40 degrees and right ascension between 0 hr and 24  hr.

The green line is the ecliptic.

What body follows this green path exactly over a year?

Q591: The reason eclipses do not happen during every orbit of the Moon is because the plane of the Moon's orbit around the Earth is tilted to the plane of the Earth's orbit around the Sun.

The diagram shows seven sequential positions of the Earth (blue) and Moon during one of their orbits around the Sun (orange).

A total eclipse of the Sun occurs in position 1. At which of the points shown in the rest of the orbit is an eclipse of the Moon most likely?

Q592: The Earth spins on its axis once in approximately 24 hours. This motion is responsible for 

1. day and night
2. summer and winter
3. the phases of the moon

Q593: The Moon orbits the Earth in 28 days. Which of these statements is/are false?

1. Where the shadow of the Moon falls on Earth there is an eclipse of the Sun
2. An eclipse of the Sun only happens at a new moon
3. The plane of the Moon's orbit is not the same as the plane of the Earth's orbit around the Sun

Q594: The Sun and the stars revolve daily about the sky. The Sun appears to move more slowly so that it drifts through the pattern of the stars. Which of these facts explains both of these observations?

1. The axis of the Earth is tilted
2. The Earth spins once a day
3. The Earth orbits the Sun

Q595: The table shows the celestial coordinates (right ascension and declination) of four of the brightest stars. 

Which star appears below the celestial equator?

Q596: Which position is the Moon in when it is full?

Q597: What is a sideral day?

Q598: A sidereal day is the time it takes for the Earth to rotate 360°. Compared to a solar day of 24 hours it is . . .

Q599: During a solar eclipse . . .

Q. A unit of electricity (1kWh) costs about 15p. How much will it cost to leave a 100 watt security lamp on for 6 hours a night for a week?

Q. What is the power rating of an electric iron that uses a voltage of 230 V and a current of 5 A?

Q. Approximately what current is a hairdryer rated 1.6kW expected to draw from a 230 V supply?

Q. To boil enough tapwater for a particular teapot requires 240 000 joules. How long will it take a kettle to do this if it is rated at 1.5 kW?

Q. A unit of electrical energy is a kilowatt-hour. This is a much greater amount than the joule. What is another expression for a kWh?

Q. Which of these is not a way to use 20 kWh of electrical energy?

Q. A unit of electrical energy is a kilowatt-hour. This is a much greater amount than the joule. How would you calculate the number of joules in a kWh?

Q607:. Which of these kettles draws approximately 6.5 A from the 230 volt mains

Q608: A householder left home for a 14 day holiday. She left five 100 watt filament lamps on a timer switch so they would come on for 8 hours each day.

How many units of electricity did she use?

Q. The table shows the heat energy lost per second from a house where the interior is maintained at 20 degrees.

The heaters needed to supply 4 kJ of heat energy every second to maintain this temperature. 

Insulating the attic by laying fibreglass on the floor will reduce the heat loss to 700 J/s

What will be the power that heaters will have to produce to maintain this temperature after the attic has been insulated?

Q.  Electricity can be generated from many energy sources. Which of these methods involve steam?

1. hydro electric
2. geothermal
3. nuclear

Q.  Electricity can be generated from many energy sources. Some methods are cleaner than others?

Which of these methods does not release carbon dioxide?

1. biofuels
2. geothermal
3. nuclear

Q. Why are radio waves used for communications with satellites?

1. they can pass through a vacuum
2. they can pass through the Earth
3. they can pass through the atmosphere

Q. These statements are meant to be advantages of optic fibres over copper wires for communications.

Which one is not true?

Q. What radiation is used for transmitting TV broadcasts?

Q. An advantage of wireless communications over wired communications is:

Q. Optic fibres are used instead of copper wires for many signalling applications. Which of these statements is NOT true?

Q617:. How is infra-red radiation used for communication in the home?

Q. Some chemical reactions can be triggered by electromagnetic radiation. One such reaction occurs with low intensity ultra violet but not with high intensity visible light.

Which of these statements is not correct?

1. the frequency of light is greater than ultra-violet
2. the higher the frequency, the less energy in each photon
3. a photon needs to exceed a certain minimum energy to trigger this chemical reaction

Q. Which of these is an advantage for copper rather than fibre optic cables?

Q620: Which electromagnetic waves are used for mobile phone communications?

Q. How many different values are there in a digital code?

Q. Which of the following statements about digital signals is false?

Q.The units of information to be transmitted or stored by a digital system, are:

Q. Which kind of signal can only have a small number of discrete values?

Q. The more information stored in an image . . .?

1. the longer it takes to transmit the image
2. the more memory required to store the image
3. the stronger the signal to transmit it

Q626: To transmit an image in a digital form it has to be divided up into a series of picture-elements (pixels). If a much larger number of pixels is used ..

1. the quality of the digitised image is greater
2. the time it takes to transmit the image is longer
3. the amount of memory needed to store the image is greater

Q. Decide which words would best complete this passage about a radio transmission system

Radio signals have to be _______  because the further they travel the more they decrease in intensity.

As they travel they pick up unwanted _______, which reduces the signal's ________

When the signal is amplified the noise is also amplified. It is easier to remove the noise if the signal is ________

Q628: When a gas is heated in a limited space the pressure increases. This is because the particles (molecules or atoms or nuclei) take up heat energy by moving faster. Which of the following are consequences of the faster motion?

1. the particles cause a bigger force when they collide
2. the particles collide more often
3. the particles get smaller

Q. Which of these temperatures is the hottest?

Q. How would the Kinetic Theory of Gases explain the pressure of a gas increasing when the volume of the container is reduced?

1. The molecules slow down
2. The molecules hit the walls harder
3. The molecules hit the walls more often

Q631: A volume of gas in the early years of the formation of a protostar increases its temperature from -223°C to +227°C without changing volume.

By how much did the pressure increase?

Q632: A gas is compressed slowly to 1% of its volume, without a change in temperature. What will be the change in its pressure?

Q633: The gas in a bottle is heated from -73 °C to 127 °C

By what percentage has its absolute temperature increased?

Q. A convex lens has a focal length of 5 cm. What is its power in dioptres?

Q. A convex lens has a power of 10 dioptres. What is its focal length?

Q. Isaac has a telescope with two convex lenses. X has a focal length of 5 cm. Y has a power of 2 dioptres.

What is the magnification of this telescope?

Q. Jeff has two convex lenses and wants to use them to make a telescope to look at the moon. X has a focal length of 12 cm and Y has a focal length of 60 cm. Which of the following statements is true?

Q638: The diagram shows some wavefronts approaching a different material at a certain speed. Their speed in the new material will be less. What else will change as the wave passes into the new material?

1. the wavelength will decrease
2. the frequency will increase
3. the direction moves up (towards X)

Q639: When a ray of light passes through a glass prism it usually bends twice.

Which of these statements about this phenomenon is/are true?

1. this effect is because light speed is different in glass
2. the effect is greatest for red light
3. the effect is called diffraction

Q640: The diagram shows waves approaching a boundary (blue) which is tilted towards the direction of motion of the wavefront. 

The wave speed is less when it travels through the blue material.

Which of these statements about the waves when they pass into the blue material is/are true?

1. the wavelength increases
2. the frequency increases
3. the direction changes towards X

Q641: The diagram shows some wavefronts approaching a different material at a certain speed.

Their speed in the new material will be less.

What else will change as the wave passes into the new material?

1. the wavelength will decrease
2. the frequency will increase
3. the direction moves up (towards X)

Q642: The diagram shows some rays of light passing through a lens.

In which direction will ray Y go?

Q643: The diagram shows some rays of light passing through a lens.

In which direction will the green ray go?

Q644: A student has two convex lenses. He is going to make an experimental telescope. Which of the lenses should be used as the eyepiece?

Q. Two Cepheid variable stars, X and Y, with the same period are identified. X is known to be 133 parsecs away and appears to be 100 times as bright as Y.

A good estimate for the distance to Y is 

Q. Which of these is less the further you go from a particular star?

1. its temperature
2. its luminosity
3. its apparent brightness

Q647: The parallax angle to a star has been measured. The angle is 0.1 arcseconds. 

How far away is the star (in parsecs)?

Q648: The parallax angle to two stars, X and Y, has been measured. X has an angle of 0.04 arcseconds and Y has an angle of 0.05 arcseconds.

Which star is nearer and what is its distance in parsecs?

Q649: A star that appears a certain brightness could be a very luminous star a great distance away or a not very luminous star which is quite close. Astronomers need a way to work out how luminous a star is.

Which of these is not a means to judge the luminosity of a star

Q650: Star X has been observed on two occasions, 6 months apart, from the Earth, in positions Y and Z as it orbits the Earth.

Star X appears in a constellation of distant stars including 1,2,3,4 and 5 in the diagram.

In March, star X appears between stars 1 and 2.

In September star X appears in in the same position as star 4

The half-angle between these two directions is shown, w = 0.02 arcseconds.

What is the distance from the Sun to star X?

Q651: The graph shows the recession speed of a number of galaxies plotted against their distance away.

What is the recession velocity of the galaxy that is 1 Megaparsec away?

Q652: Which of the distances below is typical for neighbouring stars in the Milky Way?

Q. In order to estimate the distance to a newly discovered Cepheid variable star, the brightness (apparent magnitude) has to be measured. What is important about this measurement?

Q654: The parallax angles from Earth to two stars, X and Y, have been measured. X has an angle of 0.15 arcseconds and Y has an angle of 0.75 arcseconds.

The distance to Y is 1.33 parsecs or about 4.3 light years.

Approximately what distance is X from the Earth?

Q655: What does the observed intensity of light from a star depend upon?

Q. A lift motor produces mechanical power of 920 watts when it is powered by a 230 volt supply delivering a current of 10 amps. What is its efficiency?

Q. The Sankey diagram relates to a diesel engine. 

. 

This Sankey diagram relates to a petrol engine

Which of these statements is/are true for these particular examples?

1. the diesel is more efficient
2. the petrol engine is 60% efficient
3. all the energy is accounted for

Q. To claim that electric cars are clean and do not contribute to CO2 emissions is unfair because . . .

Q. The table shows the heat energy lost per second from a house where the interior is maintained at 20 degrees.

What will be the power that heaters will have to produce to maintain this temperature?

Q660: Which of these statements about electricity generation is true?

1. during electricity generation some energy is destroyed
2. during electricity generation some energy is converted to heat
3. during electricity generation some energy is created

Q. The Sankey diagram relates to a human. 

. 

This Sankey diagram relates to a diesel engine.

Which of these interpretations is wrong?

Q. A domestic heater could be less than 100% efficient. Which reasons is/are true?

1. not all the electrical energy is converted into heat
2. not all of the heat goes where it is required
3. it might not be switched on

Q663: For each 1000J of electrical energy used by a hair dryer, 100J of kinetic energy is given to hot air and 850J of heat energy is given to the air.

How efficient is the hair dryer??

Q664: A rechargeable 2.0 volt battery supplies a current of 0.5 ampères for 30 minutes before it needs recharging.

The charger uses 2.5 volts with a current of 1.0 ampères for 40 minutes.

How efficient is the battery?

Q. Which of these changes will NOT produce a lower electricity bill?

Q. Work out the payback time for each of these changes

1. Jacket for hot water tank. Cost £20. Annual saving £30
2. Energy saving bulbs. Cost £80 Annual saving £160
3. Double glazing. Cost £3000 Annual saving £150
4. Loft insulation. Cost £1200 Annual saving £150

Which has the shortest payback time and which has the longest?

Q. In the USA the daily energy use per person is in excess of 100 units. Few people use this amount of energy directly, but it is their share of the energy used in manufacturing. The production of iron and steel and other metals and their manufacture into cars, ships, planes, fridges etc. require large amounts of energy. Which of the following changes would NOT reduce the average energy consumption?

Q. Why is it considered that promoting public transport is good for saving energy and reducing greenhouse gases?. 

1. more use of public transport means fewer cars are in use
2. fewer cars on the roads means vehicles can travel more smoothly and more efficiently
3. fewer cars means fewer parking spaces required in towns

Q. In 2013, a householder paid £720 a year for electricity. Amongst other things the electricity was used to heat water. On January 1st 2014, he had solar panels put on the roof to provide hot water. The solar panels cost £2 550.

In 2014, the householder’s bill was £570 for electricity

Estimate the payback time for the solar panels

Q670:. Which of these policies would not be expected to reduce the world's energy consumption

Q671:. Why are high voltages used for electricity distribution?

Q. What is the function of the turbine in a coal-fired power station?

Q673: In a power station, a step-up transformer is used to increase the . . .  ?

Q674: Here is an attempt to explain how extra demand is met in a coal-fired power station. Which of these is/are true ?

1. the greater the current drawn from the transformer the greater the current in the generator
2. the greater the current in the generator the bigger the force needed to rotate it
3. the greater the force opposing the turbine, the greater the steam pressure has to be

Q675: Which form of energy commonly used in the home has the lowest distribution costs

Q. Electricity can be generated from many energy sources. Which of these sources is renewable?

Q. This question is about choosing an energy source for a new power station. 

Why is a power station for geothermal energy expensive to build?

Q678:. Here are five energy sources:

• gas
• hydro-electric
• nuclear
• oil
• wave

Which two use fossil fuels?

Q679:. Here are five energy sources:

1. gas
2. hydro-electric
3. nuclear
4. oil
5. wave

Which two do not require a boiler to generate electricity?

Q680: Which of these renewable energy sources is reliable?

1. wind
2. waves
3. biofuel

Q681: Why is there a global energy problem? 

Which of the following is NOT a reason?

Q. It is proposed to build a new 100 MW power station, but the question is which sort to build. 

Which of these primary sources of energy would make the least demand for the area of the Earth's surface required?

Q683: Which kind of power station has the greatest decommissioning costs?

Q684: Which of these is a significant cost associated with nuclear power rather than gas or coal?

Q685: Which of these is a fuel for nuclear power?

Q686: What common adjustment should be made if a nuclear reactor is not producing enough heat at a time of day with high demand for electricity?

Q687: People who work at a nuclear power station are more likely to suffer from contamination by a radioactive material. Which of the following incidents is likely to lead to contamination?

1. standing close to the reactor building
2. handling fuel rods without protective clothing
3. inhaling radioactive gases

Q688: In the atoms of a nuclear fuel, energy is released from . . .

Q689: What kind of radiation is emitted by radioactive waste which will injure humans ?

Q. A nuclear reactor includes a moderator (e.g. graphite), control rods (e.g. boron), fuel rods (e.g. uranium) and a container (e.g. steel and concrete).

Which of these statements is correct?

1. the purpose of the uranium is to absorb neutrons
2. the purpose of the graphite is to slow down the neutrons
3. the purpose of the boron is to provide the fissionable atoms

Q691: Two charges, both positive, are exerting forces on each other.

Which of these statements is/are true?

1. X experiences a force to the left
2. like charges attract
3. Y experiences a force to the left

Q692: Electric current is a flow of . . .

Q693: Here are some statements about conductors and insulators. Which is/are true?

1. most metals are conductors
2. in a conductor there are many charges able to move
3. in an insulator there are few charges able to move

Q694: In an electric circuit the role of the battery is to . . 

Q695: Which of these best describes current in a circuit?

Q696: Which of these best describes potential difference?

Q697: Two charges, one positive and one negative, are exerting forces on each other.

Which of these statements is/are true?

1. X experiences a force to the left
2. unlike charges attract
3. Y experiences a force to the left

Q698: Here are some statements about conduction in metals. Which is/are true?

1. most metals are conductors
2. metals have many charges which are free to move
3. currents in metals are the movement of positive charges

Q. Uranium 238 decays to thorium 234 by emitting an alpha particle. Thorium 234 then decays to protactinium 234 by emitting a beta particle.

The atomic number of uranium is 92. What is the atomic number of protactinium?

Q. Which of these particles is found in a typical nucleus?

1. neutron
2. proton
3. electron

Q. Which of the following is explained by the strong nuclear force?

Q. How many protons are there in the nucleus of an isotope denoted 

Q703: Oxygen has 8 electrons in a neutral atom. What is the difference between oxygen-16 and oxygen-18?

Q704: Why don't positively charged particles in the nucleus fly apart from each other?

Q705: What is the direct effect of ionising radiation?

Q. U-235 and U-238 are examples of . . ?

Q. A carbon 14 isotope is shown by this symbol. In a neutral atom of carbon-14 how many electrons, protons and neutrons does it contain?

Q708: The table shows some isotopes of plutonium.

Plutonium has an atomic number of 94. Uranium has an atomic number of 92.

Which of these isotopes could decay to Uranium - 238 by a single emission?

Q709: In a famous scattering experiment alpha particles were directed at a thin piece of gold foil.

At the time the atom was seen as ball of positively charged, massy material with electrons embedded in it, like currants in a bun.

This view changed because . . 

1. more alpha particles were absorbed than expected
2. more alpha particles passed through undeflected than expected
3. more alpha particles bounced back than expected

Q. Which of the following is not a situation in which radioactive sources are commonly used?

Q711: Ionising radiation can cause harm to humans.

Which of these is/are true statements?

1. high doses cause radiation sickness
2. low doses can cause cancer
3. ionising radiation is used in hospitals

Q. A source of alpha particles is used in a smoke detector.

A small volume of air between two electrodes will conduct when alpha particles from the source cause ionisation.

Smoke particles, if present, cling to the ions and stop them moving between the electrodes?

Which of these statements is true?

Q. Some radioactive isotopes are used in medicine as tracers. They are injected into people and progress around the body. They can be monitored with an external detector.

Which of these is the most suitable isotope for this purpose?

Q714: High doses of ionising radiation will kill all living cells. Internal cancers can be treated by this radiation. If this radiation can be directed carefully, and focussed, it can be used to kill cancer cells inside the body.

Which of these sources will be the most appropriate?

Q715: High doses of ionising radiation will kill all living cells. Internal cancers can be treated by this radiation. If this radiation can be directed carefully, and focussed, it can be used to kill cancer cells inside the body.

Which of these sources will be the most appropriate?

Q716: Which of the following is not a medical use of radioactive isotopes?

Q. Why is gamma radiation sometimes used in food production?

Q. The diagram shows a fission reactor. What are the functions of the control rods and the moderator?

Q719: What kind of particle keeps a fission reaction going?

Q. Which of these is an advantage of nuclear power over fossil fuels?

Q721: What is the purpose of the coolant in a nuclear reactor?

1. to make working conditions better in the reactor building
2. to pass the heat energy to the boiler
3. to make sure the reactor core doesn't overheat

Q. The mass of a uranium-235 atom is about 20 times the mass of a carbon atom.

X. When carbon combines with oxygen in a chemical reaction, energy is released. 

Y. When a uranium nucleus splits into a barium and a krypton nucleus, energy is released.

Which of the statements below is NOT true?

Q723: Which of these particles is most likely to trigger the fission of a Uranium 235 atom?

Q724: Why does a nuclear reactor get hot?

Which of these statements helps to explain this?

1. when an atom of uranium splits, the fragments move at high speed
2. infra red radiation is emitted with each fission
3. in a hot material the atoms are vibrating with a lot of kinetic energy

Q. The activity of a radioactive sample is 960 Bq. Two hours later the activity has fallen to 30 Bq. What is the half-life of this source?

Q726: The table shows some isotopes of plutonium.

If you had a 1 gram source of each isotope, which would have the greatest activity?

Q727: Radon 222 has a half-life of  92 hours

A sample of Radon 222, with an activity of 5000 units, is freshly prepared in a sealed flask at 11.00 am on Tuesday

It is examined at 7:00 am on Saturday (92 hours later)

What changes would you you expect?

1. the activity is now 2500 units
2. the half-life is now 46 hours
3. the mass of the contents of the flask will be half

Q728: The activity of a sample is 800 units. An hour later the activity is 200 units.

What is the half-life?

Q729: The half-life of a particular isotope is 15 minutes.

At one time the activity of a sample of this isotope is 192 units.

What would you expect its activity to be after an hour?

Q. A freshly prepared sample of pure Radon-220 has been obtained.

Radon-220 is unstable and decays into Polonium-216 with a half-life of 56 seconds

Polonium-216 is also unstable and decays into Lead-212 with a half-life of 0.15 seconds

Lead-212 is also unstable and decays into Bismuth-212 with a half-life of 11 hours

Which of these statements is/are true?

1. Radon-220 is less stable than Polonium-216
2. all of the decays release alpha radiation
3. after an hour, at least 90% of the sample will be Lead-212

Q. two radioactive sources are examined. X has an activity of 200 Bq and a half-life of 10 minutes. Y has an initial activity of 1600 Bq and a half-life of 4 minutes

After how long will the activity of both sources be the same?

Q. Which of the following is sufficient protection from gamma rays?

Q. Which of the following occupations is not thought to be high-risk for exposure to radiation

Q. Which of these statements is not true?

Q735: Which of these techniques is NOT used to dispose of Intermediate level waste?

Q736: Which of these are problems of high level waste?

1. it is so radioactive that it gets very hot
2. the activity will last for thousands of years
3. small amounts could cause widespread contamination

Q737: The effects of low doses of ionising radiation are cumulative. 

This means that even exposure to low levels of activity can cause harm if they are experienced regularly.

Miners who are exposed to radiation regularly as part of their jobs are vulnerable.

Which of the following is NOT an appropriate precaution?

Q. Which of the following is a source of background radiation?

1. electricity pylons and power lines
2. naturally occuring isotopes in the soil
3. naturally occuring isotopes in the air

Q. A subject spending a day clearing up the Chernobyl site gets an average dose of 20 mSv. What factors does a radioactive dose take into account?

1. amount of radiation directed at the body
2. type of radiation
3. age of subject

Q. What units are radiation doses measured in?

Q. Which categories of radioactive waste from a power station are disposed of, when cooled, by sealing in glass then placing in steel canisters and concrete cases and then burying far underground?

Q. An iodine isotope used in medicine has a half-life of 60 days.

One used source has an activity of 1000 counts per minute

Background radiation is about 60 counts per minute.

After how long would this source be considered safe?

Q. Which of the following is a NOT a source of background radiation?

Q. Which of the following can divide a beam of white light into a spectrum of different colours?

1. a mirror
2. a prism
3. a diffraction grating

Q. Why dont microwaves escape through the holes in the mesh on the window but light does?

Q. The diagram shows the dark lines seen in the spectrum of visible light from a star

Use the table below to identify the elements present in this star.

Which of these elements is not present?

Q747:. How does the electromagnetic radiation emitted by a hotter star differ from the radiation emitted by a cooler star?

1. the peak frequency is lower
2. the total energy emitted is greater
3. the radiation goes faster

Q748: A salesman is trying to explain why a good quality optical telescope will be large. Which of these statements is/are true?

1. the larger the diameter of the objective lens, the sharper the image
2. the longer the focal length of the objective the greater the magnification
3. the larger the diameter of the objective lens the more light is captured

Q749:. What is the name given to the phenomenon in which waves spread out after passing through a gap?

Q750: When designing a radio telescope which of the following considerations are valid?

1. the larger the wavelength the greater the effects of diffraction
2. the bigger the dish the more radiation will be captured
3. some wavelengths do not pass through the atmosphere

Q. What processes are involved in transporting energy to the surface of a star

1. conduction
2. convection
3. radiation

Q. Which of these phases will a star similar to the Sun go through

Q. What happens in the radiative zone of a star?

Q. Arrange these steps in sequence for the formation of a main sequence star

1. an equilibrium is reached and the core pressure and temperature stabilises
2. the temperature increases as the material is compressed
3. a cloud of dust and hydrogen starts to contract under gravity
4. radiation from the core pushes the material away from the core
5. high temperatures and pressures in the core enable fusion reactions to begin

Q. Which of the following stages will a star go through before it ends up as a neutron star?

1. red giant
2. main sequence
3. supernova

Q. Identify the following stars on the HR diagram above

1. Betelgeuse
2. Sirius
3. Barnards Star

Which statement below is true?

Q. Refer to the three-stage fusion reaction above.  Which statement below is true?

1. a positron has the same mass as a proton
2. a positron has the same charge as an electron
3. a positron has the same charge as a neutron

Q. Where has most of the iron that is found on the Earth come from?

Q759: What is the force that triggers the formation of a star from a cloud of dust and gas?

Q760: What happens in the core of a main sequence star?

Q761: On this Hertzsprung-Russell diagram, what type of stars are in region 1?

Q. What is the correct order of the different layers in a star, starting from the centre?

Q. Which of the following stages will a star go through before it ends up as a white dwarf?

1. red giant
2. main sequence
3. supernova

Q. This graph is a Hertzsprung-Russell diagram used for comparing different stars. The vertical axis represents the luminosity (absolute brightness) of a star. The curved arrow represents the progress we expect the Sun to make after it stops fusing hydrogen in its core. 

Star X is very different from the Sun. What stages do you expect it to go through after it stops fusing hydrogen?

Q765: This is a Hertzsprung-Russell diagram with the usual axes.

The positions of the Sun and four other stars are marked.

Which star has both a much higher temperature and a much greater luminosity than the Sun?

Q766: These equations show the reactions that take place when hydrogen nuclei fuse to form helium nuclei.

In addition to helium nuclei, what else is produced?

Q. Which of the following are advantages of having telescopes controlled by computer?

1. computer controlled telescopes can be operated remotely
2. computer controlled telescopes can be directed precisely
3. computer controlled telescopes can be coordinated with each other

Q. Why do big telescopes use motors while taking photographs?

1. the Earth is spinning
2. long exposures are necessary
3. they have to be relocated to different parts of the world

Q. Which of the following are advantages of co-operation between astronomers from different countries?

1. The cost of an observatory can be divided up
2. Data from observations will be shared more readily
3. The choice of locations is bigger

Q. Which of the following do scientists think make alien existence more likely?

1. there is a vast number of stars in the universe
2. the conditions for life on a planet are very limited
3. extrasolar planets have been identified

Q771: Some of the best pictures of distant galaxies come from telescopes in space such as the Hubble Telescope.

This is because . . .

Q. Which of the following is a disadvantage of co-operation between astronomers from different countries?

Q. Which of the following is an advantage for a possible site for an observatory?

1. close to heavy industries
2. well above sea level
3. an area of high rainfall

Q774: Which of these types of telescopes is only used from space?

Q775: Why is it essential to be able to use telescopes on different parts of the Earth?

Q776: A car is moving under the influence of two horizontal forces. 

Which of these statements could describe its motion?

1. forwards (moving to the left) at a steady speed
2. reversing but slowing down
3. increasing forward speed

Q777: The skydiver is moving under the influence of two vertical forces. 

Air resistance is currently 750 newtons upwards

Weight is 750 newtons downwards

Which of these could describe the motion of the skydiver?

Q778: Heber Curtis and Harlow Shapley have been presented with a platinum globe as an award for work in astronomy. Both want to take the award home. They are both pulling the globe but it is completely stationary. The diagram shows the weight and the pull from Heber. In which direction must the pull from Harlow be acting?

Q779: A plane is flying under the influence of 4 forces. Which of these is not one of them?

Q. The diagram shows some of the forces acting on a car of mass 800 kg.

The driving force, T is 2000 newtons.

Which of these statements is true?

Q781: The skydiver is moving under the influence of two vertical forces. 

Air resistance is upwards, opposing motion

Weight is 750 newtons downwards

The skydiver is currently accelerating downwards.

Which statements is/are true?

1. the speed of the skydiver is increasing
2. air resistance is less than 750 newtons
3. the skydiver is moving at terminal velocity

Q782: Two astronauts, X and Y, are floating in a large open dome. X wants to get to the outer part so he attempts to propel himself by pushing against Y's back.

Which of these statements is/are true?

1. X and Y will both experience a force
2. the force X exerts on Y will be in the opposite direction to the force on X
3. the two forces are exactly equal, irrespective of who pushed

Q783: An orange placed on a table can remain at rest if the table exerts an upwards force on the orange equal to the weight of the orange.

Which of these statements is/are true?

1. these two forces acting on the orange are an interaction pair
2. the force the table exerts on the orange is called a 'reaction' (or 'contact') force
3. the orange exerts a force on the Earth and a force on the table

Q784: Why do you have to be careful stepping forward out of a small boat onto a landing platform?

1. the boat is much heavier than you
2. in order to get a forward force you have to push the boat back
3. if the boat moves back there will be a bigger space to jump

Q785: A plane is flying under the influence of 4 forces.

The plane is increasing its forward speed but remaining at the same height.

Which of these statements is/are true?

Q786: Which of these is/are experiencing a resultant (unbalanced) force?

1. a stone falling off a cliff
2. a car moving at constant velocity
3. a raindrop falling at terminal velocity

Q787: At the moment a skydiver pulls the cord to the parachute it is possible that the air resistance force is greater than the weight.

At that moment . . .

Q788: Which of these conditions will cause the most current in a component?

Q789: A power station supplies 200 MW to the National Grid, at a voltage of 400kV. What is the current supplied?

Q790: When a battery is connected to a bulb, 120 joules of energy (heat and light) are emitted each minute.

At what rate is the battery working?

Q791: A bulb is rated 6 watts when connected to a 12 volt battery. What current flows?

Q792: A bulb is rated 6 watts when connected to a 12 volt battery. What current flows?

Q793: A bulb passes a current of 0.3 amps when connected to a 1.5 volt battery. What is its resistance?

Q794: A 6 volt battery is connect across a 120 Ω resistor. What current flows?

Q795: What voltage battery would you need to drive a current of 0.5 ampères through a bulb with resistance 24 ohms?

Q796: What is the name of a component that conducts better when hot?

Q797: What is the symbol of a component that conducts better when light is shone on it?

Q798: A circuit is connected with a battery, a resistor and a bulb, together with three other components to measure all the voltages and currents in the circuit.

Which is the correct combination?

Q799: A circuit is connected with a battery, a resistor and a bulb, together with three ammeters.

Which ammeter will give the current through the bulb?

Q800: This circuit is supposed to be used to obtain a set of pairs of readings for the current through the bulb and the potential difference across it?

What component should be inserted between X and Y?

Q801: This circuit is supposed to be used to obtain a set of pairs of readings for the current through the bulb and the potential difference across it?

What component should be inserted between X and Y?

Q.A single cell provides a potential difference of 1.5 volts. Which of these batteries provides 9 volts?

Q. This circuit is being used to find the resistance of the coil.

Several pairs of readings are taken and a graph will be plotted.

Some reasons have been presented for the use of the components X, Y, Z. Which of the responses is is not totally correct?

Q804: Henrietta is investigating how the resistance of a wire varies with the length of wire.

This is the circuit she uses

This is the graph she obtained. It shows current in amperes on the vertical axis and length of wire in cm on the horizontal axis

She expected that the resistance would be proportional to the length.

Which of these statements is/are true?

1. the resistance of short lengths was higher than she expected
2. the shorter lengths passed lower currents than longer lengths
3. wires have greater resistance when hot

Q805: Three circuits are made using resistors as shown below. All the individual resistors have the same resistance.

Which circuit will have the highest resistance and which circuit will have the lowest resistance?

Q806: In this circuit

Which of these statements is/are true?

1. the current through each resistor is the same
2. the current through the battery is the same as the current through the bulb
3. the voltage across the bulb is the same as the voltage across the battery

Q807: In this circuit

The two resistors are not equal.

Which of these statements is/are true, ?

1. V1 = V4
2. V1 = V2
3. V2 = V3

Q.For the circuit shown, 

which of these statements is/are true?

1. the voltage across the battery equals the sum of the voltage across R1 and the voltage across R2
2. the voltage across R2 equals the voltage across L1
3. the current through L1 equals the current through R1

Q.For the circuit shown, what are the minimum numbers of ammeters and voltmeters required to work out every voltage and current?

Q810: This circuit has four ammeters.

The bulb is a better conductor (has lower resistance) than either resistor

Which of these statements is/are true?

1. A1 = A2 = A3 = A4
2. A3 = A4
3. A2 = A3 + A4

Q811: This bulb is glowing

For this circuit, which of these statements is/are true?

1. the current through the battery is the same as the current through the bulb
2. the voltage across the battery is the same as the voltage across the resistor
3. the voltage across the bulb is the same as the voltage across the resistor

Q. Which of these appliances does not use a motor?

Q813: A student has constructed an electric motor, as shown. 

She wishes to reverse the direction of rotation.

Which of these changes will achieve that?

1. reversing the battery connections
2. swapping the N and S poles of the magnet
3. both together

Q. Which direction is the force on the XY part of this coil?

Q815: In order to get the current from the supply to the coil of a motor a commutator is used with sliding contacts ('brushes').

Which of these are reasons for this

1. to isolate the supply from the magnetic field
2. to prevent the wires getting twisted after a few turns of the coil
3. to reverse the direction of the current every half turn

Q816: The output of a motor is kinetic energy of the coil. Where does this energy come from?

1. the electrical supply pushing a current round the coil loses energy
2. the magnetic field of the magnets loses energy
3. from the gravitational potential energy of the coil

Q817: Which of these household devices will not use a motor?

Q818: Moving a magnet towards a coil induces a current in the coil.

Which of these changes will increase the size of the current?

1. use a stronger magnet
2. move the magnet away instead of towards
3. have more turns in the coil

Q819: Which of these descriptions is closest to UK mains supply?.

Q820: Which device converts motion energy into electrical energy?

Q821: What is the name given to the phenomenon that causes a current to flow in a wire when it is in a changing magnetic field?

Q. Which of the following does not affect the size of the induced voltage produced by a generator?

Q. What is the mains voltage in the UK?

Q. A transformer has 1000 turns on the primary coil and 250 turns on the secondary? What primary voltage will be needed to get 20 V a.c. from the secondary?

Q825:. A step-up transformer will

1. increase the size of a direct voltage
2. decrease the size of an alternating voltage
3. increase the size of an alternating voltage

Q826: A power station supplies 200 MW to the National Grid, at a voltage of 400kV. What transformer will be required to convert this to 10,000 volts?

Q827: The primary of a transformer is connected to a 12V a.c. supply.

The primary coil has 200 turns and the secondary coil has 50 turns.

What is the output of the secondary?

Q828: A transformer consists of two coils on a soft iron core.

The secondary voltage is caused directly by

Q829: A student has set up this circuit to measure the current through and the voltage across two components.

Setting the supply to several different voltages the student collects several pairs of readings. This graph is plotted

Estimate the reading of A1 when the supply was set at 4.0 volts

Q. A transformer has 1150 turns on the primary coil and 30 turns on the secondary? The primary is connected to a 230 V a.c. supply. What voltage will the secondary produce?

Q831: The primary of a transformer is connected to a 12V dc supply.

The primary coil has 200 turns and the secondary coil has 50 turns.

What is the output of the secondary?

Q832: What is the name for this kind of angle?

Q833: This diagram shows a circle with some lines and shaded areas.

What is the line z called

Q834: This diagram shows a circle with some lines and shaded areas.

What is the line w called?

Q835: This diagram shows a circle with some lines and shaded areas.

What is the area x called?

Q836: This diagram shows a blue line crossing two parallel lines

Angles 2 and 4 are equal because they are . . .

Q837: This diagram shows a blue line crossing two parallel lines

Angles 3 and 5 are . . .

Q838: This diagram shows a blue line crossing two parallel lines

Angles 6 and 2 are equal because they are . . . 

.Q839: None of these chords passes through the centre. One is a bit close but it just misses.

What is the value of angle x?

Q840: Which of these angles is the same value as angle 5?

Q841: Two parallel lines are traversed by two other lines.

What is the value of the marked angle?

Q842: O is the centre of this circle. 

The angle RPQ is 55 degrees.

What is the value of the angle RQO?