Question

The mechanical energy can be completely converted into heat energy but the whole of the heat energy cannot be converted into mechanical energy.

(a) True

(b) False

I got this question during an online interview.

My question is from Specific Heat and Thermodynamics topic in division Kinetic Theory of Gases of Engineering Physics I

Answer 1

Right answer is (a) True

To explain: The whole of mechanical energy can be absorbed by the molecules of the system in the form of their kinetic energy. This kinetic energy gets converted into heat. But the whole of the heat energy cannot be converted into work as a part of it is always retained by the system as its internal energy.