# Homework Help: Electrostatics Problem

1. Sep 19, 2016

### Phhysics Lover

• Member advised to use the homework template for posts in the homework sections of PF.
A point charge q is placed at a distance 2r from center O of a conducting charged sphere of radius r .Due to the induced charges on the sphere ,find electric potential at point P on surface of sphere [if Kq/r=18V]

I tried this
at point P
Vnet=Vinduced+Vcharge
now Vcharge=kq/3r
but I cannot find way to calculate Vnet to find Vinduced

Assume a uncharged sphere of radius r and a charge q is kept at distance 2r from center and P is point diametrically opposite to q See second image

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2. Sep 20, 2016

### haruspex

Consider an element of induced charge qi on the sphere. Where might it be located? What is its contribution to the potential at the centre of the sphere? What is the total contribution of all such induced charge to the potential at the centre of the sphere?

3. Sep 22, 2016

### rude man

We need the potential on the surface, not the center, of the sphere.
Only way I know of approaching this problem is via imaging. Are you (the OP) familiar with that technique?

4. Sep 22, 2016

### haruspex

It's a conductor, no internal charges, and OP is first trying to find Vnet at P.