An air bubble of volume '$V_1$'  is at the bottom of a lake of depth  '$d$',  where the temperature is ${\mathrm{T}}_1.$   The bubble rises to the surface, which is at a temperature of  ${\mathrm{T}}_2$. Assuming that the bubble’s air is at the same temperature as that of the surrounding water, the volume of the bubble at the surface is (Let  $P_0$  is the atmospheric pressure and  $P_1$  is the pressure at  $T_1$ )