A neutral copper block is polarized as shown in Figure 14.90, due to an electric field made by external charges (not shown). Which arrow (a–j) in Figure 14.90 best indicates the direction of the net electric field at location B, which is inside the copper block ?

The electric field is referring to a region that is beneficial for a charged particle to exert force on another charged particle.

Also,the magnitude of the electric field is zero inside a conductor but it has some value on the surface of the conductor.

The concept of the electric field gives the direction of the net electric field at location B.

The other arrows apart from j are the incorrect representation of the direction as they are directed in the other direction with some value of magnitude. But, the magnitude of the electric field is zero inside a conductor.

When a particular conductor is placed inside an electric field, the net charges mainly lie on the conductor’s surface and thus, no electric field remains inside a conductor. However, as point B lies inside the copper block then the net electric field at point B is mainly zero and also the direction of the net electric field at point B is also zero.

Thus, the arrow j best indicates the direction of the net electric field at location B, which is inside the copper block.