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 distances r is:

directed perpendicular to the plane of plate and towards the plate

The correct answer is Option (3) → directed perpendicular to the plane of plate and towards the plate

Charging by induction is a method used to charge an object without touching the object to any other charged object.

According to charging by induction technique, when a point charge, -q is placed at a distance r from an isolated conducting plane, some positive charge develop on the surface of plane towards the charge and an equal negative charge develop on opposite side.

Hence, the field at a point P on other side of the plane is directed perpendicular to the plane and toward the plate.