Question
Two identical plane metallic surfaces A and B are kept parallel to each other in air separated by a distance of 1.0 cm as shown in the figure. Surface A is given a positive potential of 10 V and the outer surface of B is earthed, (i) What is the magnitude and direction of uniform electric field between points Y and Z? (ii) What is work done in moving a charge of 20 μC from point X to Y. Where X is situated on surface A?
Solution
Given,
Seperation between the plane metallic surfaces=1 cm = 10-2 m
Potential given to surface A, V= 10 V
Outer surface B is earthed such that, charge flows out.

Seperation between the plane metallic surfaces=1 cm = 10-2 m
Potential given to surface A, V= 10 V
Outer surface B is earthed such that, charge flows out.

(i) Electric field between the points Y and Z
(ii) Surface A is given a constant potential of 10V. Therefore, the potential difference between X and Y is given as
Work done is W=
= 0
Therefore, no work is done in moving a charge from X and Y.