Question

Two identical point charges are placed at the two vertices A and B of an equilateral triangle of side \( l \). The magnitude of the electric field at the third vertex P is \( E \). If a hollow conducting sphere of radius \( l/4 \) is placed at P, the magnitude of the electric field at point P now becomes:

• A. \( >E \)
• B. \( E \)
• C. \( \frac{E}{2} \)
• D. zero

Hint:

The electric field inside a conductor is always zero in electrostatic equilibrium.

Answer 1

The Correct Option is D

Two identical point charges at vertices A and B of an equilateral triangle produce an electric field at point P. The electric field at P due to the two charges is \( E \).
When a conducting sphere is placed at point P, the electric field inside a conductor is always zero. This happens because the free charges in the conductor rearrange to cancel any external electric field.
Thus, the electric field at point P becomes zero after the conducting sphere is placed, corresponding to option (D).