A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of $2.5\times 10^{-2} N/m$. The pressure inside the bubble equals at a point $Z_{0}$ below the free surface of water in a container. Taking $g=10 m/s^{2}$, density of water = $10^{3}kg/m^{3}$ , the value of $Z_{0}$ is: