When the soap bubble of radius R = 0.25 cm is charged, it experiences an outward electric pressure of magnitude $\frac{{\sigma }^2}{2{\epsilon }_0}$  where its surface charge density $\sigma =20\mu {\text{ C/m}}^2$, If $Q$  is the charge on the sphere so that the pressure inside and outside is same, then the surface tension of soap solution is  $\alpha \times {10}^{-12}/8{\epsilon }_0{\text{ Nm}}^{-1}$. Find the value of $\alpha$.