Question

Which one of Fe, Ag and Pb is best conductor of heat?

Answer 1

1. The energy required to remove electrons from a metal surface is very low. Therefore, when the metals are heated, the electrons on the surface of metals become free and move around the metal. During the movement, the electrons collide with each other and the kinetic energy is converted to heat energy. This heat gets propagated throughout the metal. Therefore, metals are good conductors of heat.
2. The extent of the conductivity of heat depends on the number of free electrons in the metal. The number of free electrons is maximum in Silver $\left(\mathrm{Ag}\right)$ than compared to iron (Fe) and lead (Pb). The free electrons of Silver are easier to move (high electron mobility) than in any other metal.
3. Therefore, Silver is the best conductor of heat.