An air bubble of radius 1.0 mm is observed at a depth of 20 cm below the free surface of a liquid having surface tension $0.095 \mathrm{~J} / \mathrm{m}^{2}$ and density $10^{3} \mathrm{~kg} / \mathrm{m}^{3}$. The difference between pressure inside the bubble and atmospheric pressure is $\_\_\_\_$ $\mathrm{N} / \mathrm{m}^{2}$. (Take $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )