Which of the following processes is reversible?
- Transfer of heat by conduction
- Transfer of heat by radiation
- Isothermal compression
- Electrical heating of a nichrome wire
Answer
(3) Isothermal compression
Solution
As per NCERT, a process is reversible if it is quasi-static (the system stays in equilibrium with the surroundings at every stage) and has no dissipative effects.
Heat transfer by conduction or radiation occurs across a finite temperature difference, so it is irreversible, and electrical (Joule) heating of a wire is dissipative, so it is irreversible too.
A slow (quasi-static) isothermal compression, however, can be reversed along the same path, so it is reversible.
Answer: (3)