Free Thermal expansion questions for IGCSE Physics (0625), part of Thermal physics. Each question has the answer and the marking points an examiner would look for.
Generate a full Thermal Expansion worksheet →All Thermal physics questionsA bimetallic strip is made of brass and iron, which are straight and joined at room temperature. Brass expands more than iron for the same rise in temperature.
Which metal is on the outside of the curve when the strip is heated, and when it is cooled below room temperature?
| heated | cooled | |
|---|---|---|
| A | iron | brass |
| B | brass | brass |
| C | brass | iron |
| D | iron | iron |
Answer: C
Which expands the most for the same rise in temperature?
Answer: D
A metal lid is stuck tightly on a glass jar. Running hot water over the lid makes it easier to unscrew.
Explain why.
A bimetallic strip is made of brass and iron joined together. Brass expands more than iron. State and explain what happens to the strip when it is heated.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | metal expands more than glass the metal lid expands more than the glass for the same temperature rise B1 so the lid becomes looser B1 | 2 |
| (b) | bends with brass on the outside brass expands more than iron B1 so the strip bends with the brass on the outside of the curve B1 | 2 |
Liquids expand more than solids for the same temperature rise.
A glass bottle full of water is sealed and heated. Explain why it may crack.
Explain why electricity cables sag more in summer than in winter.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | water expands more than glass water expands more than the glass B1 it pushes on the bottle with a large force B1 | 2 |
| (b) | cables expand when hot cables expand in hot weather B1 so they become longer and hang lower B1 | 2 |
Railway tracks are laid with small gaps between the rails.
Explain why the gaps are needed.
Explain, in terms of particles, why a solid expands when heated.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | rails expand in hot weather in hot weather the rails expand B1 without gaps they would push against each other and buckle B1 | 2 |
| (b) | particles vibrate more, move further apart particles vibrate with more energy B1 the average separation of the particles increases B1 | 2 |
This question is about thermal expansion.
Explain why gaps are left between sections of railway track.
A steel bridge is 800 m long. Steel expands by 1.2 × 10−5 of its length for each 1 °C rise. Calculate the increase in length when the temperature rises by 30 °C.
Compare the expansion of solids, liquids and gases for the same temperature rise, and explain the difference.
Describe how a liquid-in-glass thermometer works.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | rails expand in hot weather; gaps prevent buckling the rails expand in hot weather B1 gaps stop the rails pushing on each other and buckling B1 | 2 |
| (b) | 0.288 m 800 × 1.2 × 10−5 × 30 C1 0.288 m A1 | 2 |
| (c) | gases most, solids least; forces between particles weakest in gases gases expand most and solids least B1 liquids in between B1 forces between particles are strongest in solids and weakest (negligible) in gases B1 | 3 |
| (d) | liquid expands when heated; rises up narrow capillary tube against scale the liquid expands as temperature increases B1 it moves along a narrow capillary tube against a calibrated scale B1 | 2 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in