Question

Compute the amount of work involved in transferring a charge of two Coulombs

a) from the negative to the positive electrode;

b) from the negative electrode to the positive electrode along a 45 degree angle;

c) from the negative electrode to the positive electrode and then back to the first one;

d) along an equipotential line

Change in position	Voltage/potential difference
6cm (closest to negative electrode)	-8.61
5cm	-7.24
4cm	-5.97
3cm	-4.67
2cm	-1.75
1cm (closest to the positive electrode)	-0.85

Answer 1

Work done in moving a charge q in varying potential,
W = q ( Vf - Vi)
where Vf is potential at final position, Vi is potential at initial position

a) W = 2( -0.85 - (-8.61) )
        = 15.52 J

b) work done, depends only on the final and initial potential, not on the path followed
so W = 15.52 J

c) As charge comes back to initial potential, work done = 0

d) Along equipotential line means, charge is moving along the line, along which potetial remain same, hence W=0