The work done to increase the volume of $2$ moles of an ideal gas from $V$ to $2V$ at a constant temperature $T$ is $W$. The work to be done to increase the volume of $2$ moles of the same gas from $2V$ to $4V$ at the same constant temperature $T$ is:

One mole of an ideal gas expands at a constant temperature of $300 \, K$ from an initial volume of $10 \, L$ to a final volume of $20 \, L$. The work done in expanding the gas is ...... $J$. $(R = 8.31 \, J/mol \cdot K)$

Two identical vessels $A$ and $B$ with frictionless pistons contain the same ideal gas at the same temperature and the same volume $V$. The masses of gas in $A$ and $B$ are $m_A$ and $m_B$, respectively. The gases are allowed to expand isothermally to the same final volume $2V$. The changes in pressures of the gas in $A$ and $B$ are found to be $\Delta P$ and $1.5 \Delta P$, respectively. Then

Can two isothermal curves cut each other?

Can a system be heated and its temperature remain constant?

$A$ poly-atomic molecule $(C_v = 3R, C_p = 4R$,where $R$ is the gas constant) goes from phase space point $A (P_A = 10^5 \ Pa, V_A = 4 \times 10^{-6} \ m^3)$ to point $B (P_B = 5 \times 10^4 \ Pa, V_B = 6 \times 10^{-6} \ m^3)$ and then to point $C (P_C = 10^4 \ Pa, V_C = 8 \times 10^{-6} \ m^3)$. The path $A$ to $B$ is adiabatic and the path $B$ to $C$ is isothermal. The net heat absorbed per unit mole by the system is: