In the following indicator diagram, the net amount of work done will be

If the door of a refrigerator is kept open, then which of the following is true

Two cylinders $A $ and $B$ fitted with pistons contain equal amounts of an ideal diatomic gas at $300\ K.$ The piston of $A$ is free to move while that of $B$ is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $30\ K,$ then the rise in temperature of the gas in $B$ is  ....... $K$

Given diagram shows an ideal gas taken from state $1$ to $2$ through optional paths, $A,B,C.$ Let $Q,W$ and $U$ represent the heat supplied to, the work done by gas and the internal energy of the gas, respectively. Then which of the following conditions is true?

A cyclic process $ABCA$ is shown in $PT$ diagram. When presented on $PV$, it would be

A Carnot engine operating between temperatures $T_1$ and $T_2$ has efficientcy $\frac{1}{6}$ . When $T_2$ is lowered by $62\,K$, its efficiency increases to $\frac{1}{3}$ . Then $T_1$ and $T_2$ are, respectively