For an ideal gas of diatomic molecules,which of the following relations is correct?

For a monoatomic ideal gas,the universal gas constant $R$ is $n$ times the molar heat capacity at constant pressure $C_P$. Here,$n$ is ......

The molar specific heats of an ideal gas at constant pressure and volume are denoted by $C_{P}$ and $C_{V}$ respectively. If $\gamma = \frac{C_{P}}{C_{V}}$ and $R$ is the universal gas constant,then $C_{V}$ is equal to

The molar specific heat of an ideal gas at constant pressure and constant volume is $C_{p}$ and $C_{V}$ respectively. If $R$ is the universal gas constant and the ratio of $C_{p}$ to $C_{V}$ is $\gamma$,then $C_{p}$ is equal to:

If $C_p$ and $C_v$ are molar specific heats of an ideal gas at constant pressure and volume respectively,if $\gamma$ is the ratio of the two specific heats and $R$ is the universal gas constant,then $C_p$ is equal to

$A$ cylinder of fixed capacity of $44.8 \, L$ contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of the gas in the cylinder by $20.0^{\circ} C$ will be .............. $J$ (Given gas constant $R = 8.3 \, J \, K^{-1} \, mol^{-1}$).