A Charged soap bubble of radius 1cm is in equilibrium state. What will be the charge on the bubble? why? ST of bubble is 40 * 10 power (-3).

divide the bubble into two hemispheres. In equilibrium, mutual attraction due to surface tension=electrostatic repulsion.The charge is equally divided between the two hemispheres, and is uniformly divided on the surface of each hemisphere. Calculating the repulsion caused by this charge is an easy job.