Question

A tiny charged pellet of mass m is suspended at rest between two horizontal, charged metallic plates. The lower plate has a positive charge and the upper plate has a negative charge. Which statement in the answers here is not true?

(a) The electric field between the plates points vertically upward.
(b) The pellet is negatively charged.
(c) The magnitude of the electric force on the pellet is equal to mg.
(d) The plates are at different potentials.

 

 

Answer 1

Given that, a tiny charged pellet of mass ‘m’ is suspended at rest between two horizontal charged metallic plates. The lower plate is positively charged and the upper plate is negatively charged as shown

 

Obviously, the electric field between the plates is directed upwards and since the charge is at rest, the magnitude of electric force is equal to weight of the pallet and the plates are also at different potentials.

 

Hence the wrong statement given in the options is the pallet is negatively charged.

 

Hence the correct option is (b).

The correct option is (b).