) Two metal plates are connected to a power supply as shown in the figure below.
The separation distance between the plates is 40mm. The switch S is closed so that a potential
difference of 1.2KV is applied across the plates.
i. Give two characteristics of the electric field between the metal plates. [2]
ii. Calculate the electric field strength E between the metal plates. [3]
(b) The switch S is opened and the plates lose their charge. Two very small metal spheres A and
B joined by an insulating rod are placed in between the metal plates as shown in the figure
below.
Spheres A and B have charges –e and +e respectively, where e is the charge of a proton.The rod is
supported at its centre C so that it is horizontal and in equilibrium.
The switch S is then closed so that a p.d of 1.2KV is applied across the plates.
i. Calculate the force experienced by sphere A due to the electric field of the between the plates. [3]
ii. State and explain magnitude and direction of the force experienced by sphere B due to the electric
field between the plates. [2]
