Question

Explain the need of sink for a heat engine

Answer 1

Need of the cold body in heat engine. Purpose of heat engine is to transfer heat into the useful work, basically. Working object either gas or liquid takes heat from a thermal energy reservoir as a result of which their internal energy increases and this energy is somehow used to do work.

Answer 2

sink is behave like a heat reservoir and it heat capacity is very large and it absorbs whatever heat you have given it and remains at a constant temperature