A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of $2.5 \times 10^{-2}$ $\frac{ N}{m}$. The pressure inside the bubble equals at a point $Z_0$ below the free surface of water in a container. Taking $g = 10 \frac{m}{s^2} $ density of water $= 103\frac{ kg}{m^3}$, the value of $Z_0$ is :-
