Answer to Question #73744 in Electric Circuits for Akash Kumar kheti

Question

A positive 20µC charge is placed at the centre of a circle of radius 20 cm. If we
move a positive 2µC charge once along the circumference of the circle, will any
work be done in the process? Justify your answer.

Answer 1

The work is

A=q(φ_1-φ_2 )

where q is the charge moving along the circumference of the circle; φ_1,φ_2 are potentials at start and finish points of moving charge, which is done by the charge placed at the centre of a circle.

φ_1=φ_2=q_1/(4πε_0 R)

where q_1 is the charge at the centre of circle, R is radius of the circle, ε_0 is the electric constant. So, A=0