To understand the behavior ofthe electric field at the surface of a conductor, and itsrelationship to surface charge on the conductor.

A conductor is placed in an external electrostatic field. Theexternal field is uniform before the conductor is placed within it. The conductor is completely isolated from any source of current orcharge.

PART A)
Which of the following describes the electricfield inside this conductor?

It is in thesame direction as the original external field.
It is in theopposite direction from that of the original externalfield.
It has adirection determined entirely by the charge on itssurface.
It is alwayszero.
PART B)
The charge density inside theconductor is:

0
non-zero;but uniform
non-zero;non-uniform
infinite

PART A

It is always zero

PART B

Answer is : 0

Explanation:

PART A :It is always zero because according to my research, The net electric field inside a conductor is always zero. If the net electric field were not zero, a current would flow inside the conductor. This would build up charge on the exterior of the conductor. This charge would oppose the field, ultimately (in a few nanoseconds for a metal) canceling the field to zero.

PART B: You already know that there is a zero net electric field inside a conductor; therefore, if you surround any internal point with a Gaussian surface, there will be no flux at any point on this surface, and hence the surface will enclose zero net charge. This surface can be imagined around any point inside the conductor with the same result, so the charge density must be zero everywhere inside the conductor. This argument breaks down at the surface of the conductor, because in that case, part of the Gaussian surface must lie outside the conducting object, where there is an electric field.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.