Which statement best explains why a metal rod conducts thermal energy much more rapidly than a wooden rod of the same size?
The atoms in the metal are much larger and can store more thermal energy than the molecules in the wood.
The wood has a much higher density, which prevents lattice vibrations from passing through easily.
The metal contains free (delocalized) electrons that move quickly and transfer kinetic energy, whereas the wood has no free electrons.
Thermal energy in the wood can only be transferred by radiation, which is much slower than conduction.
301 exam-style questions on CIE IGCSE Physics 2.3 Transfer of thermal energy, covering 2.3.1a Thermal conductors and thermal insulators, 2.3.1b Explaining thermal conduction, 2.3.2 Convection, 2.3.3a Thermal radiation, 2.3.3b Surface colour and texture, 2.3.3c Rate of emission and absorption of radiation, and 2.3.4 Consequences of thermal energy transfer. Each one has a worked solution and a mark scheme showing where the marks go.