**1. The problem statement, all variables and given/known data**

**2. Relevant equations**

**3. The attempt at a solution**

I can extend the bigger cap with charge density ##\rho_2## and make it a complete sphere. If I do this, I must replace the smaller cap of charge density ##\rho_1## with a cap (of same dimensions) of charge density ##\rho_1-\rho_2##. Now this doesn’t look right to me because if I continue to find the force of interaction with the help of this new configuration, the force turns out to be attractive as ##\rho_1 – \rho_2## is negative where as the force should be repulsive. :confused:

Any help is appreciated. Thanks!

http://ift.tt/1hPfLPZ