Question

Choose the correct options for the following statements :

A) First law of thermodynamics specifies the conditions under which a body can use its heat energy to produce the work.
B) Second law of thermodynamics states that heat always flows from hot body to cold body by itself.

• A. Both A and B are true
• B. Both A and B are false
• C. A is true but B is false
• D. A is false B is true

Answer 1

The correct option is D A is false B is true

First law of thermodynamics just states that $dQ=dW+dU$.

It does $not$ tell us whether the process is feasible or not neither does it provide any condition to under which the body uses any energy.
Hence, A is false.

Second law of thermodynamics states that heat always flows from hot body to cold body by itself and for heat to flow from a cold body to hot body, external work should be done.

Thus, B is true.