# Charge on two concentric spherical shells

1. May 10, 2015

### brianeyes88677

There are two spherical shells in different sizes and they are concentric. Now if I connect a battery to the two spheres (connect the negative pole to the smaller sphere and connect the positive pole to the bigger sphere). Will this system become stable? Or is there any situation for the charges on these spheres stay static?

2. May 10, 2015

### Staff: Mentor

Sure. Do you expect something else?
You are connecting a battery to a capacitor (assuming the shells are conducting).

3. May 10, 2015

### brianeyes88677

If it is a capacitor then what's the ratio of the amount of charges on the both sphere? (the radii are r and R)

4. May 10, 2015

### Staff: Mentor

Is this homework? If yes, please post the full problem statement and your work so far.

What do you think?

5. May 10, 2015

### brianeyes88677

This is not a homework, it's just a concept that flash through my mind. If it is a capacitor just like you say, the amount of charges on the two spheres should be the same, but I think this isn't reasonable, how can it be stable if the amount of charges are the same?

6. May 10, 2015

### Staff: Mentor

Yes, this is given by charge conservation.
Where is the problem?

7. May 11, 2015

### lonely_nucleus

No, the system will not become stable because the smaller sphear has shaper edges, charges are more concentrated on sharper surfaces(smaller spheare).

8. May 11, 2015

### Staff: Mentor

Wait, what is meant by "stable" here? In terms of electric charge distribution, or in terms of forces if we don't have supports? I assumed the former one, where the different charge density is not an issue.