Positive 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 positive point charge is moved from (-a, 0,0) to (0, a, 0) is
positive
negative
zero
depends on the path connecting the initial and final positions
The two point charges are at z-axis(0,0,a/2)&(0,0,-a/2).
So, x-y plane is the plane for the dipole where the potential is zero.
Therefore moving a charge in any direction on x-y plane will do no work.(W=qV)