Question

Why is the cooling unit of a refrigerator made at the top?

Answer 1

Reason behind it is convection Current, when air becomes hot it become less dense and it shift upward that is why the cooling it is made at the top so that it may cool the hot air reaching to top from lower areas and cool air being more dense shifts downward so this shifting result in a current of air called convection current.

Note- Convection is a way of heat transfer like conduction and radiation are.