The excess pressure inside a spherical soap bubble of radius 1 cm is balanced by a column of oil $(Sp.gr=0.8),2$ mm high, the surface tension of the bubble is :

Question

\[\begin {array} {1 1} (1)\;3.92\;N/m & \quad (2)\;0.0392 \;N/m \\ (3)\;0.392\;N/m & \quad (4)\;0.00392\; N/m \end {array}\]