Charged ball within spherical shell charge problem

[Tilted]

Homework Statement

A small charged ball lies within the hollow of a metallic spherical shell of radius R. Here, for three situations, are the net charges on the ball and shell, respectively:

1 +4q, 0
2 -6q, +10q
3 +16q, -12q

(a) Rank the situations according to the charge on the inner surface of the shell, most positive first (use only the symbols > or =, for example 2=3>1).
Incorrect: Your answer is incorrect.

(b) Rank the situations according to the charge on the outer surface, most positive first (use only the symbols > or =, for example 2=3>1).





The attempt at a solution

I found part b.) to be 1=2=3 but I'm not sure how I would go about doing part a.)

 

[SammyS]

Homework Statement

A small charged ball lies within the hollow of a metallic spherical shell of radius R. Here, for three situations, are the net charges on the ball and shell, respectively:

1 +4q, 0
2 -6q, +10q
3 +16q, -12q

(a) Rank the situations according to the charge on the inner surface of the shell, most positive first (use only the symbols > or =, for example 2=3>1).
Incorrect: Your answer is incorrect.

(b) Rank the situations according to the charge on the outer surface, most positive first (use only the symbols > or =, for example 2=3>1).

The attempt at a solution

I found part b.) to be 1=2=3 but I'm not sure how I would go about doing part a.)

What do you get for the amount of charge on the inner surface of the shell in each case?

(Use Gauss's Law.)