Two bodies A and B at temperatures ' $\mathrm{T}_1$ ' K and ' $\mathrm{T}_2$ ' K respectively have the same dimensions. Their emissivities are in the ratio $16: 1$. At $\mathrm{T}_1=\mathrm{xT}_2$, they radiate the same amount of heat per unit area per unit time. The value of $x$ is

In an isobaric process of an ideal gas, the ratio of heat supplied and work done by the system $\left(\frac{\mathrm{Q}}{\mathrm{W}}\right)$ is $\left[\frac{\mathrm{C}_{\mathrm{P}}}{\mathrm{C}_{\mathrm{V}}}=\gamma\right]$.

The temperature of a body on Kelvin scale is ' $x$ ' $K$. When it is measured by a Fahrenheit thermometer, it is found to be ' x ' ${ }^{\circ} \mathrm{F}$. The value of ' $x$ ' is (nearly)

For a gas at a particular temperature on an average, the quantity which remains same for all molecules is