2 Fig. 2.1 shows a hollow metal cube filled with boiling water. The temperature of the four vertical surfaces are equal but each surface has a different colour or texture. metal cube thermal radiation sensor meter 40 shiny white surface Fig. 2.1 A thermal radiation sensor is placed the same distance from each surface and the meter reading measures the thermal radiation emitted from each surface. (a) The results are shown in Fig. 2.2. Draw a line linking each type of surface with the appropriate meter reading. One line has been drawn for you. type of surface dull black dull white shiny black shiny white meter reading 40 60 80 100 Fig. 2.2 [2] (b) The hot surfaces produce a convection current in the air outside the metal cube. Describe how the convection current is produced. … … … … … [3] [Total: 5]

2(a) dull black line 100 B1 dull white 60 and shiny white 40 B1 2(b) hot air rises B1 density of hot air less (than cold air) or air expands on heating B1 hot air rises and cold air falls or a complete current described B1

3 A hot steel rod is cooled by plunging it into cold water, as shown in Fig. 3.1. steel rod Fig. 3.1 (a) The steel rod has a mass of 2.0 kg and is initially at a temperature of 500 °C. It cools to 50 °C when placed in the water. The specific heat capacity of steel is 460 J / (kg °C). Calculate the thermal energy (heat) lost by the steel rod as it cools to 50 °C. thermal energy = … [3] (b) A small mass of water boils when the rod is placed in the water. The remaining water then cools to room temperature and some of it evaporates. In both boiling and evaporation, water molecules escape into the air. (i) State one way in which boiling is different from evaporation. … … … [1] (ii) The rate of evaporation decreases as the water cools. Explain why this happens, using ideas about molecules. … … … [2] [Total: 6]

3(a) (E =) mcT in any form algebraic or numerical C1 2 × 460 × 450 C1 4.1 ×× 105 J A1 3(b)(i) any one of: • boiling occurs at one temperature / boiling point or evaporation occurs at any temperature / below boiling point • boiling occurs within liquid or evaporation occurs on the surface • evaporation increased by draughts, more surface area (and boiling does not) B1 3(b)(ii) (average) speed / K.E. of molecules decreases (as temperature falls) or (molecules) do not have the energy to escape / break bonds B1 fewer fast / energetic molecules escape or (only) fastest / high KE molecules escape B1 (a) To earn marks, you must correctly use the formula E=mcΔT, either algebraically or with numbers, and substitute the correct values (including the temperature change of 450 °C). Finally, provide the correct numerical answer. (b)(i) To state a difference between boiling and evaporation, you need to mention one key distinction, such as boiling occurring at a specific temperature throughout the liquid, while evaporation happens at any temperature on the surface. (b)(ii) To explain why the rate of evaporation decreases, you must state that the average speed/kinetic energy of molecules decreases as temperature falls, leading to fewer energetic molecules escaping the liquid.

3 A type of nuclear reaction takes place at the centre of the Sun. The reaction releases thermal energy. (a) State the name of the type of nuclear reaction that takes place at the centre of the Sun. … [1] (b) Thermal energy is emitted from the surface of the Sun into space. The energy is transferred through the vacuum of space by thermal radiation. (i) Describe the radiation that is emitted from the surface of the Sun. … … … [2] (ii) State the speed of this radiation in a vacuum. speed = … [1] (iii) The Earth is 1.5 × 1011 m from the surface of the Sun. Calculate the time taken for this radiation to travel to Earth. time = … [2] (c) Explain one advantage of wearing white clothes on sunny days. … … … [2] [Total: 8]

3(a) (nuclear) fusion B1 3(b)(i) electromagnetic (waves) B1 produced by hot objects or infrared (radiation) B1 3(b)(ii) 3.0 × 108 m / s B1 3(b)(iii) (t =) x / v or 1.5 × 1011 / 3.0 × 108 C1 500 s A1 3(c) white surfaces are (good) reflectors / poor absorbers of radiation B1 less thermal energy absorbed / wearer stays cooler B1

7 A hydraulic press is used at a recycling centre to compress waste material. Fig. 7.1 is a side view of the press. waste piston 1 upper surface of piston 2 oil P piston 2 pipe ground force Fig. 7.1 (not to scale) A force to the left is exerted on piston 1. Oil is pushed along the pipe and this moves piston 2 downwards. Piston 2 compresses the waste. (a) Oil is a liquid. (i) State the property of a liquid that makes it suitable for use in a hydraulic system. … … [1] (ii) Explain, in terms of molecules, why a liquid has this property. … … … [2] (b) Suggest one advantage of using oil as the liquid in a hydraulic press. … … [1] (c) The cross-sectional area of piston 1 is 0.018 m2. Piston 1 exerts a force of 4500 N on the oil. (i) Calculate the pressure of the oil due to this force. pressure = … [2] (ii) The pressure of the atmosphere is 1.0 × 105 Pa. Calculate the total pressure of the oil in the pipe. total pressure = … [1] (iii) The area of piston 2 that is in contact with the oil is 1.4 m2. Initially, the upper surface of piston 2 is level with point P. Calculate the force exerted on piston 2 due to the pressure calculated in (c)(ii). force = … [1] (d) (i) As piston 1 moves along the pipe: • the pressure of the oil in the pipe at point P remains constant • piston 2 moves downwards • the pressure of the oil at the upper surface of piston 2 increases. Explain why the pressure at the upper surface of piston 2 increases. … … … [1] (ii) The density of the oil is 900 kg / m3. The upper surface of piston 2 is now 0.50 m below the level of the pipe. Calculate the increase in the force exerted at the upper surface of piston 2 by the oil. [gravitational field strength g = 10 N / kg] increase in force = … [3] (e) There is air trapped in the plastic bags that contain the waste. The temperature of the air in the bags remains constant. Explain, in terms of molecules, why the pressure of the trapped air increases as it is compressed. … … … … … [3] [Total: 15]

7(a)(i) liquids (almost completely) incompressible B1 7(a)(ii) molecules touching / very close B1 large (repulsive) forces between the molecules B1 7(b) (oil) reduces friction / has high boiling point / no dissolved gas / air B1 7(c)(i) (P =) F / A or 4500 / 0.018 C1 2.5 × 105 Pa A1 7(c)(ii) 3.5 × 105 Pa B1 7(c)(iii) 4.9 × 105 N B1 7(d)(i) (hydrostatic) pressure in a liquid increases with depth or weight of oil (above piston 2) increases B1 7(d)(ii) (ΔP =) hρ g or 0.50 × 900 × 10 or 4500 C1 4500 C1 6300 N A1 7(e) volume (of trapped air) decreases or molecules closer together B1 molecules collide with walls / bag / surface B1 molecules collide more often B1

Cambridge O Level Physics · 5054

O-Level Physics (5054) Thermal physics past paper questions

Revise O-Level Physics (5054) — Thermal physics with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

212 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Thermal physics in O-Level Physics 5054 exams, 2020–2025

Across 2020–2025, Thermal physics accounted for 209 questions worth 797 marks in Cambridge O Level Physics (5054) papers.

By year
Year	Questions	Marks
2020	36	121
2021	33	116
2022	35	130
2023	33	122
2024	36	165
2025	36	143

Most-tested subtopics

2.2.2 Specific heat capacity396 marks
2.2.3 Melting, boiling and evaporation207 marks
2.1.2 Particle model194 marks

Appears in

Paper 1 · 131 qs
Paper 2 · 42 qs
Paper 3 · 14 qs
Paper 4 · 22 qs

All most-tested Physics topics

2021 May/Jun · Paper 2 · Q2 · 5 marks
Marking scheme
Get Steven’s plain-English explanation
2021 May/Jun · Paper 2 · Q3 · 6 marks
Marking scheme
Get Steven’s plain-English explanation
2021 Oct/Nov · Paper 2 · Q3 · 8 marks
Marking scheme
Get Steven’s plain-English explanation
2021 Oct/Nov · Paper 2 · Q7 · 15 marks
Marking scheme
Get Steven’s plain-English explanation
2021 May/Jun · Paper 1 · Q10 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q10
Answer: A
Get Steven’s plain-English explanation