An iron rod is heated at one end. Which of the following best describes the physical mechanisms responsible for the conduction of thermal energy to the cooler end?
the migration of high-energy iron ions from the hot end to the cold end representing a flow of matter
only the vibrations of the iron ions in the lattice structure
both the vibration of iron ions in the lattice and the movement of free (delocalized) electrons along the rod
only the movement of free (delocalized) electrons along the rod
67 exam-style questions on CIE IGCSE Physics 2.3.1a Thermal conductors and thermal insulators. Each one has a worked solution and a mark scheme showing where the marks go.