Question

Work done in carrying a 2 coulomb charge in a circular orbit of a radius 3 cm around a charge of 10 coulomb is

Answer 1

Work done to carry a charge from one position to other position is given by

$W = q(V_2 - V_1)$

here

q = charge on the particle

$V_2, V_1$ = final and initial potential

now here it is given that charge is moving in a circle around another charge particle

So the potential is due to other charge particle which is given by

$V = \frac{KQ}{r}$

here r = distance from the charge

from above formula we can say that potential will remain the same on all point of the circle of fixed radius

so here on moving a charge in circle there is no change in the potential and it will be same at all points

$V_2 = V_1$

so here

$V_2 - V_1 = 0$

so work done in the above case must be ZERO