A point charge -Q is placed at a small distance r from an isolated conducting plate. The direction of the electric field at a point A on the other side of the plane at the same distance r is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → directed perpendicular to the plane of plate and towards the plate
The charge \( -Q \) induces charges on the plate: \( +Q \) on the face nearer to it and \( -Q \) on the far face, because an isolated plate stays neutral overall. The field just outside a conductor is always perpendicular to its surface.
At a point A on the far side, the field is due to the negative charge on the far face. The field of a negative charge points towards it, so at A the field is perpendicular to the plate and directed towards the plate.