Particle Theory and Thermal Physics

1. Gas is contained in a cylinder and exerts a pressure on the cylinder.

The speed of the gas molecules is reduced.

Which row shows what happens to the temperature of the gas and to the pressure exerted by the gas on the cylinder?

temperature pressure

A decreases decreases

B decreases increases

C increases decreases

D increases increases0654/12/M/J/13Q31

2. A substance is a gas when its temperature is 65°C.

How do the boiling point and the melting point of this substance compare with 65°C?

boiling point melting point

A above 65°C above 65°C

B above 65°C below 65°C

C below 65°C above 65°C

D below 65°C below 65°C0654/12/M/J/13Q32

3. A hot water tank is fitted with two identical heaters P and Q. Heater P is two thirds of the way up the tank and heater Q is at the very bottom. The tank is full of cold water.

When only heater Q is switched on, it takes a long time to heat the tank of water to the required temperature of 60°C.

What happens to the tank of cold water if only heater P is switched on?

A All the water reaches 60°C in less time than before.

B All the water reaches 60°C in the same time as before.

C The bottom two thirds of the water reaches 60°C in two thirds of the original time.

D The top one third of the water reaches 60°C in one third of the original time.

0654/12/M/J/13Q33

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4. A beaker of cool liquid stands in a warm room. The temperature of the liquid is falling because molecules are escaping from the surface of the liquid.

Which row gives the name of this process, and also shows which molecules are escaping from the liquid?

name of process molecules that are escaping

A condensation least energetic

B condensation most energetic

C evaporation least energetic

D evaporation most energetic0654/11/M/J/13 q31

5. Which row shows what happens to the temperature of a solid as it melts and what happens to the temperature of a liquid as it boils?

temperature when a solid melts temperature when a liquid boils

A increases increases

B increases no change

C no change increases

D no change no change0654/11/M/J/13 q32

6. Liquid in a beaker evaporates quickly.

Which row shows what happens to the mass and to the temperature of the liquid in the beaker?

mass temperature

A decreases decreases

B decreases increases

C increases decreases

D increases increases0654/11/O/N/13 q31

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7. A sample of liquid is allowed to cool for 20 minutes. Its temperature is recorded every two minutes.

The results are shown in the table.

How should the sample be described at the end of the 20 minutes?

A all liquid

B all solid

C in the process of boiling

D in the process of solidifying

0654/11/O/N/13 q32

8. The diagrams show part of a water-heating system which is working by convection.

Which diagram shows the flow of water in the system?

0654/11/O/N/13 Q33

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9. Two identical metal rods are 25cm long at room temperature (20°C).

One rod is put into a freezer at a temperature of –18°C. The other rod is put into an oven at a temperature of 200°C. The rods are left for several hours.

Which row shows the new length of each rod?

length of rod at –18°C length of rod at 200°C

A 25cm 25cm

B 25cm more than 25cm

C less than 25cm 25cm

D less than 25cm more than 25cm0654/13/O/N/13 q32

10. On a warm day, a driver checks the air pressure in a car tyre. Overnight the temperature drops and the air pressure in the tyre falls. There are no air leaks in the tyre.

Why does the pressure fall?

A The air molecules in the tyre move more slowly.

B The air molecules in the tyre stop moving.

C The volume of the air in the tyre decreases.

D The volume of the air in the tyre increases.

0654/11/M/J/12 Q31

11. How is heat transferred in a vacuum?

A by conduction and convection

B by convection and radiation

C by convection only

D by radiation only

0654/11/M/J/12 Q32

12. Which energy resource did not receive its energy from the Sun?

A geothermal

B hydroelectric

C oil

D waves

0654/12/M/J/12 Q30

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13. A glass bottle containing air is sealed with a screw cap and then cooled in cold water.

The contraction of the glass bottle can be ignored.

What remains the same during the cooling?

A the air pressure inside the bottle

B the energy of the air molecules in the bottle

C the force on the cap made by the air molecules in the bottle

D the volume of air inside the bottle

0654/12/M/J/12 Q31

14. What happens to the temperature of a substance as it is melting and as it is boiling?

melting boiling

A decreases increases

B decreases no change

C increases increases

D no change no change0654/12/M/J/12 Q32

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15. A hot metal ball is placed in a small hollow in a piece of wood. Two thermometers are placed equal distances from the ball, one at position P and one at position Q.

Which thermometer gives the highest reading and why?

highest reading reason

A thermometer at P the air conducts heat sideways, not upwards

B thermometer at P the wood conducts the heat sideways, not upwards

C thermometer at Q convection carries the heat upwards, not sideways

D thermometer at Q infra-red rays carry the heat upwards more than sideways0654/13/M/J/12 Q33

16. Which statement about a gas in a container of constant volume is correct?

A The less often the gas molecules collide with the container walls, the higher the pressure.

B The lower the temperature of a gas, the more often its molecules collide with the container walls.

C The pressure of a gas increases as its temperature decreases.

D The temperature of a gas increases as the speed of the gas molecules increases.

0654/11/O/N/12 Q31

17. Which statement about the transfer of thermal energy is correct?

A Heat transfer by radiation involves mainly ultraviolet radiation.

B Heat transfer by radiation requires a medium to travel through.

C The main method of heat transfer through gases is conduction.

D The main method of heat transfer through liquids is convection.

0654/11/O/N/12 Q32

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18. A gas cylinder has a constant volume.

The gas molecules collide with the walls of the cylinder at a certain rate.

The gas is heated and its pressure increases.

What happens to the average speed of the gas molecules and to their rate of collision with the cylinder walls?

average speed of gas molecules

rate of collision

A increases increases

B increases stays the same

C stays the same increases

D stays the same stays the same0654/13/O/N/12 Q31

19. Four students make statements about the change of state of solids, liquids and gases.

Which statement is correct?

A The boiling point of a liquid is the temperature at which it starts to evaporate.

B The temperature of a liquid does not change while it is boiling.

C The temperature of a liquid falls while it is solidifying.

D Heat energy must be put into a gas to make it condense.

0654/13/O/N/12 Q32

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20. Fig. 2.2 shows an iceberg floating in the sea.

(i) Which material named on Fig. 2.2 best fits the statement below?

“The particles are able to move, are randomly arranged and are closely packed.”

_________ sea water ; ________________________________________

[1]

(ii) Name the process by which water molecules in the sea become water molecules in the air.

_______evaporation ; ______________________________________________________________

[1]

0654/31/M/J/13 Q2 part

21. This is a microwave oven. The energy of microwaves is used to cook food by heating up the water molecules in the food.

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a) A student heated some water in a microwave oven for five minutes. The graph shows how the temperature of the water changed.

The temperature of the water stops increasing after two minutes.

Explain what happened to the water molecules during the five minutes.

energy is input throughout 5 minutes/at constant rate ;

up to 100°C/for first 2 minutes increase in the kinetic energy of the particles (in liquid) ;

water boils at 100°C/after 2 minutes ;

energy used to separate water molecules/break forces/bonds between molecules (not for more KE);

correct reference to Latent Heat ;

[3]

b) 0.5kg of water is heated in the microwave from 10°C to 50°C. The specific heating capacity of water is 4200J/kg°C.

Calculate the energy needed to heat the water.

State the formula that you use and show your working.

formula used (energy =) mc∆T ormsθ ormass × SHC × change in temperature ;

working

∆T= 40 ;

energy = 0.5 × 4200 × 40 = 84000J ;

________________ [3]

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c) The following label is found on a cooker that combines a microwave oven and a grill.

voltage 220V

microwave power 0.60kW

grill power 1.20kW

Some meat is cooked using both the microwave oven and the grill. Both are switched on at full power for 30 minutes.

Calculate the total energy transferred by the cooker.

Show your working.

(total power =) 1.8(kW)/1800(W);

energy = power × time/1800 × 30 × 60 ;

= 3 240 000J ;

________________ [3]

0654/32/M/J/13 Q4 part

(ii) Name the process that releases energy within the Sun.

______ (nuclear) fusion ; _______________________________________

[1]

(iii) Energy is transferred from the Sun to the Earth by radiation.

Explain why energy cannot be transferred from the Sun to the Earth by conduction.

______ (conduction) requires particles/a medium ;

only radiation can pass through a vacuum ;

[1 max]

[1]

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(c) Inside the washing machine, some of the water evaporates when the washing machine is being used.

(i) During evaporation, water changes state from liquid to gas.

Complete the diagrams to show the arrangement of particles in a liquid and in a gas.

[3]

(ii) Explain, in terms of particles, the process of evaporation.

faster moving molecules ;

can do more work against attractive forces/can break bonds between them/ owtte ;

break free/separate turn into gas/leave liquid ;

energy/heat (from surroundings) used for this ;

[3]

0654/33/M/J/13 Q8 part

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liquid particles touching and similar size ;

gas particles not touching ;

random arrangement for both ;

22. Fig. 2.1 shows the inside of a refrigerator.

The temperature inside the freezing compartment is -20°C and the temperature in the rest of the refrigerator is +5°C.

(a) (i) The air in the refrigerator is cooled by convection.

Draw one arrow on Fig. 2.1 to show the movement of the air cooled by the freezing compartment.

[1]

arrow going downwards ;

(ii) Explain this movement in terms of particles and density.

cooler air gas contracts/particles closer together/particles move slower/

particles have less kinetic energy/particles are less energetic ;

cold air is denser (therefore moves down) ;

[2]

(b) The mass of air in the refrigerator is 0.19kg.

The air in the refrigerator is cooled by 4°C.

The specific heating capacity of air is 1.01J/kg°C.

Calculate the heat energy removed from the air when it is cooled.

State the formula that you use, show your working and state the unit of your answer.

formula (energy =) mass ×SHC ×temp. change ;

working

unit

= 0.19 ×1.01 ×4 = 0.77 J ;

[2]

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(c) (i) Some ice from the freezing compartment is allowed to melt at 0°C.

Explain why energy is required to melt the ice even though the temperature remains at 0°C.

energy required, for work done against forces of attractions/to break the intermolecular forces/to break the intermolecular bonds ;

energy required for particles to break free from a solid state ;

reference to latent heat of fusion ;

[1]

(ii) Complete the diagrams to show the arrangement of water molecules in solid ice and in liquid water.

One molecule has been drawn for you in each box. Each diagram should contain at least twelve water molecules.

[2]

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solid – all particles touching, regular arrangement particles of similar size ;

liquid – at least half particles touching, irregular arrangement particles of

similar size ;

(d) A refrigerator can be warmed up by radiation energy absorbed by the outside surface of the refrigerator. Such absorption needs to be kept as low as possible.

The four refrigerators shown in Fig. 2.2 are identical except for the outside surface.

State which refrigerator is most effective at keeping the contents cool.

Explain your answer.

refrigerator D/white and shiny refrigerator (no mark)

white/light surfaces are worst absorbers/reflect most radiation ;

shiny surfaces are worst absorbers/reflect most radiation ;

[2]

0654/31/O/N/13 Q2

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23. (c) The cooling system of the car uses water to remove heat energy from the hot engine.

The heated water goes into the radiator. Heat energy is lost from the radiator.

(i) Fig. 8.1 shows a car radiator.

Explain how the features of the radiator that are shown in Fig. 8.1 increase the rate of cooling of hot water.

copper is a good conductor of heat ;

(convection off) large surface area ;

thin pipes shorter distance for conduction ;

[2]

(ii) The mass of water in the radiator is 5kg.

The specific heating capacity of water is 4200J/kg°C.

Calculate the energy released when the water in the radiator cools by 12°C.

State any formula that you use, show your working and state the unit of your

answer. energy = mass × specific heating capacity × temp change ;

formula

working

= 5 × 4200 × 12 ;

= 252000J ;

unit [3]

0654/32/O/N/13 Q8

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24.

A) (i) Fig. 6.1 gives information about the uses of different types of electromagnetic waves and their effects on living tissue.

Draw lines to link each electromagnetic wave with its effect on living tissue and its use.

One has been completed as an example.

(ii) State one property that is the same for all electromagnetic waves.

____ (wave) speed ; transverse waves ; do not require a medium ; [1 max]

[1]

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(b) Infra-red radiation is the part of the electromagnetic spectrum often involved in heat transfer by radiation.

A student carried out an experiment to find out the type of surface that was the best emitter of radiation.

She set up the apparatus shown in Fig. 6.2 and measured the temperature of the water in the flasks every minute for 20 minutes.

Her results are shown in Fig. 6.3.

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(i) From the graphs identify, with a reason, the flask that cools most rapidly.

__flask B because temperature drops most (over a period of time) ; __________

[1]

(ii) Suggest why the flask you identified in (i) cooled more rapidly than the others

__ black surfaces are good emitters of radiation; __________

[1]

(iii) State two variables which the student needed to keep constant during her experiment.

need two answers

volume of water

shape/size of flask

starting temperature of water/ambient temperature ;

[1]

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25. (b) The water used to irrigate one sugar cane farm comes from a waterfall. The farmer attempts to reconstruct an experiment which may have been carried out by James Joule in 1847.

Joule attempted to show that the water at the bottom of a waterfall was hotter than water at the top of the waterfall. His reasoning was that the water had gravitational potential energy at the top of the waterfall, which would be converted to kinetic energy as it fell. This kinetic energy would be changed to heat energy when the water fell into the pool at the bottom of the waterfall.

(i) 1kg of water has 300J of gravitational potential energy at the top of the waterfall.

State the maximum kinetic energy that 1kg of water will have when it reaches the bottom of the waterfall. Explain your answer.

maximum kinetic energy

explanation

300J AND all potential energy will be converted into kinetic energy/energy is conserved ;

[1]

(ii) Assuming that all the kinetic energy of the water is converted to thermal (heat) energy, calculate the temperature rise in the 1kg of water. The specific heat capacity of water is 4200J/kg°C.

State the formula that you use and show your working.

formula used (temperature change =) energy/mass × shc ;

working

= 300/1 × 4200 ;

= 0.07°C ;

[3]

0654/31/M/J/12 Q1 part

26. (a) A car tyre is inflated using a footpump. The mechanic using the footpump notices that the pump gets hot.

(i) Explain how the air molecules in the tyre exert a pressure on the wall of the tyre.

molecules collide with tyre wall;

force exerted causing pressure ;

[2]

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(ii) The air going into the tyre is warmed up by the pumping.

Describe what happens to the motion of the air molecules as the air warms up.

__they move faster/have more kineticenergy ; __________________

[1]

(iii) When the air in the tyre becomes hotter, the pressure rises.

Explain in terms of the motion of the air molecules why the pressure rises.

particles collide with wall more often ;

collisions, are harder/faster/have more energy ;

[2]

0654/33/M/J/12 Q4 part

27. This is a question about swimming pools

(d) The mass of water in the pool is 70000kg.

The specific heating capacity of water is 4200J/kg°C. The water is allowed to cool from 35°C to 25°C.

Calculate the energy lost by the water during this cooling.

State your answer in MJ (megajoules).

State the formula that you use and show your working.

formula used (energy =) mass × shc × change intemperature ;

working

= 70000 × 4200 × 10 ;

= 2940000000J = 2940 (MJ) ;

MJ [3]

0654/32/O/N/12 Q3 part d

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28. Fig. 6.1 shows a washing machine.

(a) A label on the back of the washing machine shows the following information.

(i) Explain what is meant by an a.c. frequency of 50Hz.

alternating current/owtte ;

which changes 50 times per second ;

[2]

(ii) Calculate the current when the washing machine is using 2kW of power.

State the formula that you use and show your working.

formula used power = voltage x current/(I=) P/V ;

working

current = 2000 ÷ 250 = 8 A ;

[2]

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(b) (i) Some of the water inside the washing machine evaporates.

Explain the process of evaporation in terms of particles.

particles separate/escape ;

more energetic particles escape (from surface) ;

able to overcome attractive forces of other particles ;

[2]

(ii) Inside the washing machine the water is heated by an electric heater.

Explain how heat energy is able to pass through the metal parts of the heater.

conduction ;

particles nearest heater (element) gain energy and vibrate more ;

vibrations/heat/energy, passed from particle to particle along the metal ;

reference to energy passing via mobile electrons ;

[2]

(c) The casing of the washing machine is a solid. The water used in it is a liquid.

Complete the diagrams below to show the arrangement of particles in a solid and in a

liquid.

[2]

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solid has particles touching in regular arrangement ;

liquid has most particles touching in random arrangement ;

(d) 3kg of water are being heated in the washing machine from 10°C to 50°C.

The specific heating capacity of water is 4200J/kg°C.

Calculate the energy required to heat the water.

Show your working and state the formula that you use.

formula used (energy =) mass × shc × change intemperature ;

working

= 3 × 4200 × 40 ;

= 504000J ;

[3]

0654/33/O/N/12 Q6

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