The pressure of a gas is proportional to

Number of molecules in a volume of $4\, cm^{3}$ of a perfect monoatomic gas at some temperature $T$ and at a pressure of $2\, cm$ of mercury is close to $?$
(Given,mean kinetic energy of a molecule (at $T$) is $4 \times 10^{-14}\, erg$,$g=980\, cm/s^{2}$,density of mercury $=13.6\, g/cm^{3}$)

An ideal gas is kept in a cylinder of volume $3 \,m^3$ at a pressure of $3 \times 10^5 \,Pa$. The energy of the gas is

The average kinetic energy of a molecule of a gas is

The kinetic energy of $1$ mole of $He$ gas at $27^{\circ}C$ is .... $J$.

If the average translational kinetic energy of a molecule in a gas is equal to the kinetic energy of an electron accelerating from rest through $10 \,V$, then the temperature of the gas molecule is (Boltzmann constant $= 1.38 \times 10^{-23} \,JK^{-1}$)