A termodynamic system is taken through the closed cycle $PQRSP$ process. The net work done by the system is ...... $J$

If a bimetallic strip is heated, it will

Choose the incorrect statement from the following

$S1$: The efficiency of a heat engine can be $1$, but the coefficient of performance of a refrigerator can never be infinity

$S2$: The first law of thermodynamics is basically the principle of conservation of energy

$S3$: The second law of thermodynamics does not allow several phenomena consistent with the first law

$S4$: A process, whose sole result is the transfer of heat from a colder to a hotter object is impossible

Two Carnot engines $A$ and $B$ are operated in series. The engine $A$ receives heat from the source at temperature $T_1$ and rejects the heat to the sink at temperature $T$. The second engine $B$ receives the heat at temperature $T$ and rejects to its sink at temperature $T_2$. For what value of $T$ the efficiencies of the two engines are equal?

In thermodynamic processes which of the following statements is not true

One mole of an ideal diatomic gas undergoes a transition from $A$ to $B$ along a path $AB$ as shown in the figure, The change in internal energy of the gas during the transition is