The ratio of the work done, change in internal energy, and heat absorbed when a diatomic gas expands at constant pressure is

The relation between efficiency $(\eta)$ of a Carnot engine and the coefficient of performance $(\beta)$ of a refrigerator working between the same temperatures is:

$A$ gas obeying the equation of state $pV = RT$ undergoes a hypothetical reversible process described by the equation $pV^{5/3} \exp \left(-\frac{pV}{E_0}\right) = C_1$,where $C_1$ and $E_0$ are dimensioned constants. Then,for this process,the thermal compressibility at high temperature

Air in a cylinder is suddenly compressed by a piston,which is then maintained at the same position. With the passage of time,

The initial state of a certain gas is $(P_i, V_i, T_i)$. It undergoes expansion until its volume becomes $V_f$. Consider the following two cases:
$(a)$ The expansion takes place at constant temperature.
$(b)$ The expansion takes place at constant pressure.
Plot the $P-V$ diagram for each case. In which of the two cases is the work done by the gas more?

When a system is taken from a state $i$ to $f$ along the path $iaf$ (as shown in the figure),$Q = 50 \, cal$ and $W = 20 \, cal$. Along path $ibf$,$Q = 36 \, cal$.
$(i)$ What is $W$ along path $ibf$?
$(ii)$ If $W = -13 \, cal$ for path $fi$,what is $Q$ for the path $fi$?
$(iii)$ Take $E_{int,i} = 10 \, cal$,then what is $E_{int,f}$?