Which statement about the transfer of thermal energy is correct?
Air is a good conductor of thermal energy, which is why trapped air is used in double-glazed windows.
Convection currents can form in solids, liquids, and gases.
In a vacuum, thermal energy is transferred solely by radiation.
Thermal radiation requires a material medium to transfer energy.
99 exam-style questions on CIE IGCSE Physics 2.3.3a Thermal radiation. Each one has a worked solution and a mark scheme showing where the marks go.