Thermal Physics Exam Questions for IGCSE Physics

This guide covers the question types you will meet in the thermal physics section of IGCSE Physics papers.

Question type 1: Specific heat capacity calculations

These questions give you a mass, a temperature change and an energy value. You use E = mc(T2 - T1) to find the missing quantity.

Worked example: 2.0 kg of water is heated from 20 degrees C to 70 degrees C. The specific heat capacity of water is 4200 J/(kg degrees C). Calculate the energy required.

E = mc(T2 - T1) = 2.0 x 4200 x (70 - 20) = 2.0 x 4200 x 50 = 420,000 J = 420 kJ.

Question type 2: Latent heat calculations

These questions involve a change of state at constant temperature. Use E = mL.

Worked example: How much energy is needed to melt 0.5 kg of ice at 0 degrees C? The specific latent heat of fusion of ice is 334,000 J/kg.

E = mL = 0.5 x 334,000 = 167,000 J = 167 kJ.

Question type 3: Heating curve interpretation

A graph shows temperature plotted against time. You must identify the flat sections (change of state), explain why the temperature is constant (energy goes into breaking bonds, not increasing kinetic energy), and identify the melting point and boiling point.

Question type 4: Particle model descriptions

Describe the arrangement, spacing and motion of particles in each state of matter. Explain what happens when a substance is heated in terms of particle kinetic energy.

Question type 5: Conduction, convection and radiation

Describe the mechanism of each type of thermal energy transfer. Explain why metals are good conductors (free electrons). Explain how a vacuum flask reduces all three types of transfer.

Practice approach

Work through one question of each type from past papers. Mark using the mark scheme. Identify which question types you find hardest and practise those again.