Question

Which of the following is the Kelvin Planck statement?

(a) Heat from a cold reservoir cannot be transferred to a hot reservoir without external work

(b) Efficiency for a reversible cyclic process can be 1

(c) Heat from a hot reservoir can be completely converted into work if process is reversible

(d) Efficiency of a heat engine is less than 1

I had been asked this question in unit test.

This key question is from Second Law of Thermodynamics in division Thermodynamics of Physics – Class 11

Answer 1

Correct option is (d) Efficiency of a heat engine is less than 1

For explanation: Kelvin Planck statement is: No process is possible whose sole result is the absorption of heat from a reservoir and complete conversion of that heat into work. So, this implies that efficiency of a heat engine is less than 1.