# Qualitative Solid Spherical Conceptual

roxnascarf9

## Homework Statement

For a charged solid metal sphere with total charge Q and radius R centered on the origin: Select "True" or "False" for each statement:

1.If the solid sphere is an insulator (instead of metal) with net charge Q, the net charge on the inside of the solid sphere is negative.
2. If the solid sphere is an insulator (instead of metal) with net charge Q, the electric field for r << R would be the same as that of a conductor with the same shape and charge.
3. The electric field inside the solid metal sphere is never zero.
4. The electric field near the metal surface on the outside is perpendicular to the surface.
5. The electric field for the metal sphere at r << R will be the same as the field of a point charge, Q, at the origin.
6. The net charge on the inside of the solid metal sphere is neutral.

## Homework Equations

Gauss's Law: Qinside/ esub0

## The Attempt at a Solution

1. False I'm not quite sure on this one

2. True I'm not quite sure on this one

3. False I;m not quite sue on this one

4. False, On the inside of a sphere the electric field is prependicular to the surface, but on the outside it wouldn't be

5. False I'm not quite sure on this one

6. True This is true becasue the net charge would be zero if the the eletric field is perpendicular.

Homework Helper
What leads you to suggest these answers - you don't have to be sure or even correct.

Last edited:
Bhumble
Welcome to PF. You should state your reasoning and not just true or false so that people can see where you are having issues.

1. Being an insulator or metal should impact the electric permittivity but shouldn't change the charge.

2. It states that they have the same shape and charge but I THINK an ideal conductor has all the charge on the surface. You should look it up to double check.

4. How is the electric field perpendicular inside and not outside? Imagine the inside and outside of a shell, what's the difference in angle?

5. Back to part 2. Unless this is suppose to be r>>R...

6. Depends on the characteristics of an ideal conductor. I'm pretty sure that the charge is all on the surface.

Homework Helper
Welcome to PF. You should state your reasoning and not just true or false so that people can see where you are having issues.
Lets let OP tell us the reasoning before providing answers ;) this is homework after all.

1. Being an insulator or metal should impact the electric permittivity but shouldn't change the charge.
But how come? Can we think of any way to get extra positive charges into a neutral insulator? Is there any way the insulator will adjust so the net charge ends up negative?

2. It states that they have the same shape and charge but I THINK an ideal conductor has all the charge on the surface. You should look it up to double check.
OR, reason it out ... what is different between a conductor and an insulator, in terms of how charges move? How will the charges affect each other?