Which of the following statements about a conductor in electrostatic equilibrium is false?
(a) the electric field inside the conductor is zero.
(b) just outside the conductor, the electrostatic field is perpendicular to its surface.
(c) the net charge inside the conductor is zero, all excess charge resides on the surface.
(d) a charge located within a hole in a conductor at equilibrium feels no force from charges outside the conductor.

All the options are correct

Explanation:

From the properties of the conductors when it is in the electrostatic equilibrium, all the given options in this problems are correct.

The option (A). is correct. This is so because the electric field inside the conductor is proportional to the negative of the gradient of the potential energy. For equilibrium potential should be minimum, therefore electric field is zero.

The option (B). is correct. This is due to achieving the static equilibrium of the surface, electric field should be perpendicular to its surface.

The option (C). is also correct. This is due to attaining static equilibrium, the charges inside the conductor should not be moving. Therefore the net charges should be zero inside the conductor.

The option (D). is correct. This is because for achieving electrostatic equilibrium, the charges inside the conductor should not moving, for this the net force experienced by the charges inside the conductor by the charges outside the conductor is zero.

the amount of current in the coil