Which of the following statements are true for a conductor in an external electric field?

(A) Inside a conductor, the electric field is non-zero.
(B) At the surface of a charged conductor, the electric field must be normal to the surface at every point.
(C) The interior of a conductor can have no excess charge in a static situation.
(D) Electrostatic potential is constant throughout the volume of the conductor and has the same value on its surface.

Choose the correct answer from the options given below:

(B), (C) and (D) only

The correct answer is Option (4) → (B), (C) and (D) only

Explanation:

(A) is incorrect — In electrostatic equilibrium, the electric field inside a conductor is zero, not non-zero.

(B) is true — Electric field lines emerge or terminate perpendicular to the surface of a conductor in electrostatic equilibrium.

(C) is true — Any excess charge resides only on the surface of a conductor in electrostatics.

(D) is true — Because the electric field inside is zero, potential remains constant throughout the conductor and its surface.

Correct answer: (B), (C), and (D)