Root mean square speed (\(V_{\text{rms}}\)) is defined as:
\[ V_{\text{rms}} = \sqrt{\frac{3RT}{M_w}} \]
Here, \(M_w\) represents the molar mass of the gas.
The ratio of root mean square speeds for helium (\(V_{\text{He}}\)) to oxygen (\(V_{\text{O}_2}\)) is calculated as:
\[ \frac{V_{\text{O}_2}}{V_{\text{He}}} = \sqrt{\frac{M_{w,\text{He}}}{M_{w,\text{O}_2}}} \]
Using the given values:
\[ \frac{V_{\text{O}_2}}{V_{\text{He}}} = \sqrt{\frac{4}{32}} = \frac{1}{2\sqrt{2}} \]
Consequently, the ratio \(V_{\text{He}} / V_{\text{O}_2}\) is:
\[ \frac{V_{\text{He}}}{V_{\text{O}_2}} = \frac{2\sqrt{2}}{1} \]

For an ideal gas, a cyclic process ABCA as shown in the P–T diagram. When represented in P–V plot, it would be 