Question

If a hot body and a cold body are kept in vacuum, separated from each other, can they exchange heat? If yes, which mode of transfer of heat causes change in their temperatures? If not, give reasons.

Answer 1

Yes, they can exchange heat even in a vacuum. Heat transfers by radiation because radiation does not require a material medium. The hot body emits more thermal radiation than the cold body, so heat is transferred from the hot body to the cold body. As a result, the hot body cools, and the cold body warms until they reach thermal equilibrium.