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

$A$ graph is drawn between absolute temperature and volume of $3$ moles of helium gas as shown in the figure. If $5 \text{ cal}$ of heat is used in the process, then the work done is (in $\text{ J}$)

The state of a thermodynamic system changes from $(1)$ $(P_1, V)$ to $(2P_1, V)$ and $(2)$ $(P, V_1)$ to $(P, 2V_1)$. The work done during these two processes is respectively:

Which one of the following equations specifies an isobaric process?
$[Q=$ heat supplied; $\Delta P, \Delta V$ and $\Delta T$ are change in pressure,volume,and temperature respectively.]

$A$ container having $1$ mole of a gas at a temperature $27^{\circ}C$ has a movable piston which maintains a constant pressure in the container of $1 \, atm$. The gas is compressed until the temperature becomes $127^{\circ}C$. The work done is ........ $J$ ($C_P$ for the gas is $7.03 \, cal/mol-K$).

$A$ sample of ideal gas $(\gamma = 1.4)$ is heated at constant pressure. If $100 \ J$ of heat is supplied to the gas,the work done by the gas is ...... $J$.