In which thermodynamic process,volume remains same?

$dQ$ is the heat energy supplied to an ideal gas under isochoric conditions. If $dU$ and $dW$ denote the change in internal energy and the work done respectively,then:

The $P-V$ diagram for an ideal gas in a piston-cylinder assembly undergoing a thermodynamic process is shown in the figure. The process is

The change in internal energy of a mass of gas, when the volume changes from $V$ to $2V$ at constant pressure $P$ is (where $\gamma$ is the ratio of specific heat at constant pressure to that at constant volume, $\gamma = \frac{C_p}{C_v}$):

Two moles of ideal helium gas are in a rubber balloon at $30^{\circ} C$. The balloon is fully expandable and can be assumed to require no energy in its expansion. The temperature of the gas in the balloon is slowly changed to $35^{\circ} C$. The amount of heat required in raising the temperature is nearly (take $R = 8.31 \ J / mol \cdot K$) (in $J$)

An ideal diatomic gas is heated at constant pressure. The ratio of the work done to the heat supplied is