The efficiency of a heat engine is $\eta$ and the coefficient of performance of a refrigerator is $\beta$. Then:

$A$ monoatomic gas at pressure $P$ having volume $V$ expands isothermally to a volume $3V$ and then adiabatically to a volume $81V$. The final pressure of the gas is $(\gamma = 5/3)$.

What is an isothermal process, adiabatic process, and isobaric process? Write the first law of thermodynamics for an ideal gas.

For a gas with adiabatic index $\gamma = 5/3$,what percentage of heat supplied at constant pressure is converted into work (in $\%$)?

In thermodynamic processes,which of the following statements is not true?

One mole of an ideal gas is taken through a cyclic process with alternating isothermal and adiabatic curves. In the $P-V$ diagram, $AB, CD, EF$ are isothermal curves at absolute temperatures $T_1, T_2,$ and $T_3$ respectively, and $BC, DE,$ and $FA$ are adiabatic curves. If $\frac{V_B}{V_A} = 2$ and $\frac{V_D}{V_C} = 2$, then for the cycle shown in the figure, four statements are made below. (Figure is not drawn to scale)
Statement $1$: Ratio of volumes $\frac{V_E}{V_F} = 4$
Statement $2$: Magnitude of work done in isothermal compression $EF$ is $2RT_3 \ln(2)$
Statement $3$: Ratio of heat supplied to the gas in process $AB$ to heat rejected by the gas in process $EF$ is $\frac{T_1}{T_3}$
Statement $4$: Net work done by the gas in the cycle $ABCDEFA$ is $(T_1 + T_2 - 2T_3) R \ln(2)$
Find the number of correct statements given for the cyclic process followed by the gas.