NEET Class neet Answered

Initially the force experienced by the charged oil droplet due to electric field and due to gravity is equal and opposite and hence the drop is at rest. When the electric field is switched off the only force acting on the drop would be gravitational force, in downward direction, and the drops will accelerate and gain velocity. If the electric field is switched on again the drop will again experience the upward electrostatic force. Now net force is zero so there will be no acceleration and the drop will move with constant velocity.