Chapter 24, Problem 38A

To determine

To explain: The possibility of conversion of heat into mechanical energy and also conversion of mechanical energy to heat along with examples.

Explanation of Solution

Introduction:

According to second law of thermodynamics, the entropy of cannot decrease and for the reversible process the entropy of the system is constant.

  $\Delta S=\frac{\Delta Q}{T}$

Where,

  $\Delta S=$ Entropy

  $\Delta Q=$ Heat

  $T=$ Temperature

The mechanical energy of a system can complete convert into the heat energy. Refrigerator, electric heater are the best example of conversion of mechanical energy into the heat energy but when a person try to convert all heat energy into the mechanical energy, then it is not possible. For example: In solar heater, it is not possible to convert all heat energy into mechanical energy due to second law of thermodynamics. If the heat energy convert into a mechanical energy entirely then the second law of thermodynamic will violate.

Conclusion:

Hence, the conversion of mechanical energy into a heat energy entirely is possible but the complete conversion of heat energy into mechanical energy is not possible.