Poistive and negative point charges of equal magnitude are kept at `(0, 0, a/2)` and `(0, 0, (-a)/(2))` respectively. The work done by the electric field when another poistive point charge is moved from `(-a, 0, 0)` to `(0, a, 0)` is

Options

A. positive in both `I` and `III`
B. negative and appears only at the point on the sphere closest to the point charge
C. zero
D. depends on the path connecting the initial and final positions

Answer

C

Explanation

`A equiv (0a, 0, 0), B equiv (0, a, 0)`

Point charge is moved from A to b
`V_(A)=V_(B)=0 :. W=0`