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
B. negatively charged
C. zero
D. depends on the path connecting the initial and final positions

Answer

1

Explanation

`V_(C) = (1)/(4 pi in_(0)) [ (-q)/(a//2) + (q)/(3a//2)]`
`V_(D) = (1)/( 4 pi in_(0)) [ (q)/( a//2) + (-q)/(3a//2)]`
`W _(C rarr D) = Q (V_(D) - V_(C))`
`= Q.(1)/(4 pi in_(0)) [ (2q)/( a//2) - (2q)/( 3a//2)] = +ve`