Find the charge on the conducting surface

[Fatima Hasan]

Homework Statement

Homework Equations

$Q_{net}=Q_1+Q2$

The Attempt at a Solution

$Q_{net}=Q_1+Q2$
$-15 = +5 + Q_2$
$Q_2=-15-5 = -20nC$

 

[Doc Al]

What's the charge on the inner surface of the shell?

 

[Fatima Hasan]

What's the charge on the inner surface of the shell?

$-15 nC$
$5-15=-10 nC$

 

[Doc Al]

$-15 nC$
$5-15=-10 nC$

That's not the charge on the inner surface of the shell. Do this: Imagine a Gaussian surface in the middle of the conducting material. What net charge must it contain?

 

[Fatima Hasan]

That's not the charge on the inner surface of the shell. Do this: Imagine a Gaussian surface in the middle of the conducting material. What net charge must it contain?

$-5 nC$ ?

 

[Doc Al]

$-5 nC$ ?

No, that's not the net charge within the Gaussian surface. Hint: What's the field within the conducting material?

 

[Fatima Hasan]

No, that's not the net charge within the Gaussian surface. Hint: What's the field within the conducting material?

The charge of the inner surface is $-15nC$
The charge of the outer surface is $+5 - 15 = -10 nC$

 

[Doc Al]

The charge of the inner surface is $-15nC$

How did you determine that?