1. The problem statement, all variables and given/known data two infinite conducting plates 1 and 2(both grounded or connected by a wire so that their potential is same) are separated by a distance l. A point charge q is located between the plates at a distance x from plate 1. find the charges induced on each plate. 2. Relevant equations 3. The attempt at a solution the book says that if the charge q is imagined to be uniformly spread over the plane passing through that charge and parallel to the plates , the charges induced on plates remains unchanged, only their distribution changes. i can solve the problem if i assume it.i will assume a certain charge distribution and field can be easily found out and using that i can find change in potential change in going from either plates to the middle plate.and that should be equal. but can anyone tell me from where that assumption came from.