Two charges `+q and -q` are located at points `A(0,0. -2) and B(0,0,2)` respectively. How much work will be done in moving a test charge from point `P (4,0,0) to Q(-5,0,0)` ?

Answer

Zero

Explanation

As shown in fig, we have an electric dipole held along Z-axis. We have to move a test charge from `P (7,0,0) to Q (-3,0,0)` on the X-axis i.e., on equatorial line of dipole
As potential on equatorial line of dipole is zero, therefore, work done
`W = q_(0) (V_(Q) - V_(P)) = q_(0) (0-0)`
= Zero