Helium gas undergoes a cycle $ABCDA$ (consisting of two isochoric and two isobaric lines) as shown in the figure. The efficiency of this cycle is nearly ....... $\%$ (Assume the gas to be an ideal gas).

An engineer claims to have made an engine delivering $10 \ kW$ of power with a fuel consumption of $1 \ g/s$. The calorific value of the fuel is $2 \ kcal/g$. Is the claim of the engineer valid?

The three processes in a thermodynamic cycle shown in the figure are: Process $1 \rightarrow 2$ is isothermal; Process $2 \rightarrow 3$ is isochoric (volume remains constant); Process $3 \rightarrow 1$ is adiabatic. The total work done by the ideal gas in this cycle is $10 \, J$. The internal energy decreases by $20 \, J$ in the isochoric process. The work done by the gas in the adiabatic process is $-20 \, J$. The heat added to the system in the isothermal process is .............. $J$.

One mole of an ideal gas at initial temperature $T$ undergoes a quasi-static process during which the volume $V$ is doubled. During the process,the internal energy $U$ obeys the equation $U = a V^3$,where $a$ is a constant. The work done during this process is

The graph for $y = 1 - e^{-x}$ is represented by (for $x > 0$):

$A$ gas expands with temperature according to the relation,$V=k T^{2/3}$,where $k$ is a constant. Work done when the temperature changes by $60 \ K$ is ($R=$ universal gas constant.) (in $R$)