question_answer

When a charged oil drop moves upwards in an electric field of strength E, the electric force acting on the drop is

A)  equal to the gravitational force

B)  less than the gravitational force

C)  greater than the gravitational force

D)  greater than the mass of the oil drop

Correct Answer: C

Solution :

                 When a charged drop moves in an electric field E, the forces acting on the block are its weight mg acting vertically downwards and force due to electric field \[E\,({{E}_{F}}=qE)\]. Since, the drop is moving upwards, the electric force acting, on the drop is greater than the gravitational force.