Aneutral copper block is polarized as shown in the figure below, due to an electric field made by external charges (notshown). which arrow (a–j) in the figure below best indicates the direction of the net electric field at location b, which isinside the copper block?

As point B is located inside the copper block so net electric field at point B is j.

Explanation:

Consider the figure attached below. The net electric field at location B,that is inside the copper block is zero because when a conductor is charged or placed in an electric field of  external charges, net charge lies on the surface of conductor and there is no electric field inside the conductor. As point B is located inside the copper block so net electric field at point B is zero as well direction of net electric field at point B is zero.

probably not if net force is zero

the higher the current the higher the mag field around it the higher the influence on the compass