Which of the following graphs between pressure $(P)$ and volume $(V)$ of a gas correctly shows an isochoric process in thermodynamics?

$A$ sample of gas expands from volume ${V_1}$ to ${V_2}$. The amount of work done by the gas is greatest when the expansion is

Air is pumped into a balloon,of initial volume $V$,until its diameter has doubled. If the atmospheric pressure is $p$,what is the work done against the atmosphere?

$A$ diatomic gas with rigid molecules does $10 \ J$ of work when expanded at constant pressure. What would be the heat energy absorbed by the gas,in this process ..... $J$.

In an isochoric process,if $t_1 = 27^{\circ}C$ and $t_2 = 127^{\circ}C$,then $\frac{P_1}{P_2}$ will be equal to [$P_1$ and $P_2$ are the pressures at $t_1^{\circ}C$ and $t_2^{\circ}C$ respectively].

Find the heat energy required to increase the temperature of $2$ moles of a monoatomic gas from $273 \ K$ to $373 \ K$. (No work is done in the process.) (in $R$)