two spheres of mass m and each charge q are hung from two silk threads of length l from the same point and they separate by a distance x .x<

find dq/dt

you have not mentioned that charged will fall due to what?kindly post correctly next time.

By the way this is question no 3 of IE IRODOV,also came in AIEEE 2011 kindly see irodovs soln or see solved paper of AIEEE 2011.