The thermodynamic process in which no work is done by the gas or on the gas is

Which one of the following equations specifies an isochoric process?
$[Q = \text{heat supplied, } \Delta p = \text{change in pressure, } \Delta V = \text{change in volume, } \Delta T = \text{change in temperature}]$

$10 \text{ mole}$ of an ideal gas is undergoing the process shown in the figure. The heat involved in the process from $P_1$ to $P_2$ at constant volume $V = 1 \text{ m}^3$ is $\alpha \text{ Joule}$ ($P_1 = 21.7 \text{ Pa}$, $P_2 = 30 \text{ Pa}$, $C_v = 21 \text{ J/K} \cdot \text{mol}$, $R = 8.3 \text{ J/mol} \cdot \text{K}$). The value of $\alpha$ is . . . . . . .

In a given process for an ideal gas,$dW = 0$ and $dQ < 0$. Then for the gas:

The change in the internal energy of $3$ moles of a gas heated at constant volume from $20^{\circ}C$ to $40^{\circ}C$ is $1080 \ J$. The molar specific heat of the gas at constant volume in $J \ mol^{-1} \ K^{-1}$ is:

The thermodynamic process in which the work done on or by the gas is zero is: