Question
A 500 μC charge is at the centre of a square of side 10 cm. Find the work done in moving a charge of 10 μC between two diagonally opposite points on the square.
Solution
The diagonally opposite points lie at equal distance from the centre of the sphere.
Let,
The distance from the centre of the square to opposite diagonal points be 'r'.
Opposite diagonal points be A and B
Therefore,
Since, VA=VB there is no potential difference across A and B.
Hence, the work done in moving a charge is 0.