Question

The electric field inside a hollow conductor placed in an external electric field is always zero as shown in the figure. This property of a conductor finds a very useful application in shielding sensitive electric equipment. Electric circuits are enclosed within metal boxes that provide shielding from external fields, thereby protecting them from external interferences. 

 

Given here is a hollow, electrically neutral spherical conductor. A positive charge q is suspended at its center. 

 

Explain with an appropriate reason if this hollow conductor shields the OUTSIDE from the field produced by the point charge inside. Represent the electric field lines diagrammatically.

Answer 1

The charge +q inside the hollow conductor induces an equal and opposite charge, that is, -q on the interior surface. 

Electric field lines inside the hollow conductor are produced that are radially directed outwards. 

Equal charge +q is induced on the outer surface of the conductor, which generates radial electric field lines directed outwards.

As the electric field outside the hollow conductor is not zero, it fails to shield its OUTSIDE from the electric field produced by the point charge on the inside.