Syllabus Edition

First teaching 2023

First exams 2025

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Thermal Equilibrium (CIE A Level Physics)

Exam Questions

1 hour7 questions
1a
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4 marks

Use the words in the box to complete the gaps in the definition of thermal energy.

 
higher            possessed               lower                   gained                temperature                heat                 movement

 

Thermal energy is defined as the energy ................................ by an object due to its ................................ .

Thermal energy is transferred from a region of ................................ temperature to a region of ................................ temperature.

1b
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2 marks

Identify, by placing a tick () next to the correct statements in Table 1.1 about energy and thermal energy. 

 
Table 1.1   
Statements Place a tick () here if correct

The conservation of energy states that energy is never created or destroyed, only transferred from one form to another.

 

When a thermometer is placed in a beaker of boiling water, the thermometer reading increases.

This is because the liquid in the thermometer is a lot warmer than the water.

 

Temperature tells us the magnitude of energy flow when two regions are in contact.

 

The mechanism by which the thermal energy is transferred is by either conduction, convection or radiation.

 

1c
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1 mark

Add an arrow to Fig. 1.1 to indicate the direction of energy flow between the 100 °C and the 0 °C region. 

  
14-1-1c-e-thermometer-thermal-equilibrium-esq-cie-a-level
Fig. 1.1
 
1d
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4 marks

The four statements in Table 1.2 describe the process of thermal energy transfer.

Order the sentences chronologically, by writing numbers 1−4 in the right column, to describe this process.

Table 1.2     

Statements about thermal energy transfer Number the stages of the process

Two regions need to be in contact for thermal energy transfer to occur.

 

The final temperature when two regions are in thermal equilibrium depends on the initial temperature difference between them.

 

Thermal energy is transferred from the hot region to the cold region.

 

The hotter region will cool down and the cooler region will heat up until they reach the same temperature.

 

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2a
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3 marks

Fig. 1.1 shows block X on a countertop. The room is kept at a constant temperature of 18°C. The temperature of block X is 15°C. 

14-1-e-q2a-sq-cie-ial-physics

Fig. 1.1

Describe the thermal energy transfer that takes place.

2b
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1 mark

Block X is left on the countertop for a couple of hours. 

Suggest a reasonable estimate for the temperature of block X after this time.

2c
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4 marks

Block X is then placed on top of blocks Y and Z, as shown in Fig. 1.2. Block Y is at a temperature of 5°C and block Z is at a temperature of 32°C.

14-1-e-q2b-sq-cie-ial-physics

Fig. 1.2

Describe the thermal energy transfers that take place.

2d
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1 mark

Blocks X, Y and Z are left on the countertop all day and all night. 

Suggest a reasonable estimate for the temperature of the blocks the following morning.

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3a
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3 marks

Ice cubes are added to a glass of cold water.

Describe the energy transfer taking place, and explain how this cools the water.

3b
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6 marks

A thermometer initially reads 20°C at room temperature. The thermometer is added to the glass of water at the same time as the ice cubes.

Describe and explain what the thermometer will show when:

(i)
the thermometer is initially placed in the glass
[2]
(ii)
the energy transfer between the ice and water has stopped
[2]
(iii)
the glass has been left on the table for several hours.
[2]

3c
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1 mark

A person comments that the ice cooled the water by transferring 'coldness' from the ice to the water.

Explain why this statement is incorrect.

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1a
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2 marks

A metal plate is heated for a few minutes until it reaches thermal equilibrium.

State and explain what is meant by thermal equilibrium in this context.

1b
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3 marks

The temperature of the metal plate rises from 25 °C to 450 °C.

On the thermodynamic scale of temperature, calculate

(i)
the temperature of 450 °C,
[2]
(ii)
the temperature rise of the block.
[1]
1c
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2 marks

Describe, in terms of particles, the transfer of energy as the metal plate reaches thermal equilibrium.

1d
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4 marks

A student states, incorrectly, that temperature measures the amount of thermal energy (heat) in a body.

State and explain two observations that show why this statement is incorrect.

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2a
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3 marks

Explain, using thermal energy transfer, why blowing on a hot coffee cools it down faster.

2b
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3 marks

Fig 1.1 shows the cooling curve for a hot cup of coffee left standing in a room.

14-1-2b-m-coffee-cooling-curve
Fig 1.1
(i)
Determine the temperature of the room.
[1] 
(ii)
Sketch on Fig 1.1 the curve for when the coffee is blown on.
[2]
2c
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5 marks

A student states that the temperature of the coffee measures the amount of thermal energy, or heat, in it.

Suggest whether this statement is correct. Explain your reasoning using two observations.

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3a
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3 marks

Describe what is meant by the terms thermal energy and temperature and explain how they are related.

3b
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1 mark

A hot piece of copper is placed into a container of cold water. After a time, the copper and water reach thermal equilibrium.

Describe how to determine whether the copper and water have reached thermal equilibrium.

3c
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2 marks

Describe how the water and copper reach thermal equilibrium in terms of thermal energy.

3d
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2 marks

The copper is removed from the water and the beaker of water is placed in a refrigerator at 0°C.

Describe what happens to the average kinetic energy of the water molecules.

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1a
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6 marks

A metal wok with a wooden handle is placed on a gas hob. The wok contains oil and the hob is switched on. A chef begins to heat the oil. 

Explain the role of conduction, convection and radiation in heating the oil. Use diagrams to help explain your answer. 

1b
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5 marks

A scientist has come across an unmarked glass thermometer containing mercury.  

Describe how the thermometer can be calibrated so it can be used to measure the temperature of objects between 0 °C and 100 °C.

1c
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3 marks

Explain and give examples of the differences between temperature and heat.

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