# Homework Help: Problem abput electricity

1. Dec 7, 2012

### shotikokobaxi

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

We have a charge Q and it's h metres far from the flat surface. Find the force with which acts on the Q charge by the surface

2. Relevant equations

3. The attempt at a solution

Last edited by a moderator: Dec 7, 2012
2. Dec 7, 2012

### Staff: Mentor

Wow! No need to shout (Big loud font)

Welcome to Physics Forums, shotikokobaxi.

What formula(s) are appropriate here? Is the flat surface a conducting surface? If so, what analysis technique is appropriate for calculating the effects of an induced charge?

Last edited by a moderator: Dec 7, 2012
3. Dec 7, 2012

### shotikokobaxi

we use kulon's force F=kq2/r2 the question is to find the force with which the surface (which hasn't any charges) acts on the Q charge

4. Dec 7, 2012

### Staff: Mentor

Yes, that's what we call Coulomb's force law for electric charges. It is applicable, but there's a special technique which can be used for cases where one charge induces a charge in an otherwise uncharged conducting surface as you have here. Look up "the method of image charges".