Question

All of the following options describe the availability and unavailable energy of a system EXCEPT:

• A. Availability depends on the system and the surroundings
• B. Availability is defined as the maximum work output obtainable from a certain heat input in a cyclic heat engine
• C. Unavailable energy is defined as minimum energy that has to be rejected to the sink by the second law
• D. When heat is transferred through the finite temperature difference, the available energy transferred remains constant

Hint:

Remember that when heat is transferred through a finite temperature difference, some of the energy becomes unavailable to do work, as dictated by the second law of thermodynamics.

Answer 1

The Correct Option is D

The transfer of heat through a finite temperature difference causes a reduction in available energy due to the second law of thermodynamics, which implies that the available energy decreases as the temperature difference reduces. Option (d) incorrectly states that available energy remains constant.