10 C of charge are placed on a spherical conducting shell. A point particle with a charge of –3C is placed at the center of the cavity. The net charges, in coulombs, on the inner and outer surfaces of the shell, is:

a. -7
b. +7
c. 0
d. +13
e. +6.5

The net charges on inner surface is +3 C

The net charges on outer surface is +7 C

Explanation:

Given that,

Charge on spherical conducting shell = 10 C

Charge at center = -3 C

We know that,

The net electric field inside the conducting shell is zero. The Gaussian surface inside the conductor must have zero net charge.

We need to calculate the net charges on inner surface

The charge on the inner surface of the conductor must be equal and opposite to the present charge of the  center.

So, The net charges on inner surface is +3 C.

We need to calculate the net charges on outer surface

Using formula of net charge

Put the value into the formula

Hence, The net charges on inner surface is +3 C

The net charges on outer surface is +7 C

iron would move it is magnetic there is a mag field around the current in the wire

cant without the picture! ?