# Simple doubt in induced charge

When a positive point charge q is brought close to a neutral conducting spherical shell then negative charges will be induced on the part of the shell closer to q and equal positive charges will appear on side of the shell farther from q.I understand this part.

But if the conducting spherical shell contains a charge +Q,then,if charge q is brought close to the shell ,what will happen ?

There are two possibilities

1) Fewer positive charges will be present on the side of shell near the charge q ,say Q1 ,and higher concentration of charges,say Q2, on the side of shell farther from q ,such that Q1+Q2=Q

2) Negative charges will be induced ,say -Q1,on side of the shell close to q and positive charge,Q1+Q will be present on the side farther from q.

I am not sure which of the possibilities is correct.

jtbell
Mentor
It depends on the magnitude of q relative to Q. If q is very small, you get your situation #1. If q is very large, you get your situation #2.

1 person
You have brought a charge +q near a charged conductor having charge +Q right? When then get closer to each other there will one force acting known as coulumb force. So the chagres might repel each other.
So when you bring them togather you have to do work.
Other things go on as jtbell suggested.

Thanks jtbell :-)

It depends on the magnitude of q relative to Q. If q is very small, you get your situation #1. If q is very large, you get your situation #2.

And in both the cases the charges rearrange themselves such that the external electric field is cancelled within the conducting metal .Correct?

vanhees71