Question -
Answer -
Charge located at the origin, q =8 mC= 8 × 10−3 C
Magnitude of a small charge, which is takenfrom a point P to point R to point Q, q1 = − 2 × 10−9 C
All the points are represented in the given figure.
Point P is at a distance, d1 =3 cm, from the origin along z-axis.
Point Q is at a distance, d2 =4 cm, from the origin along y-axis.
Potential at point P, 
Potential at point Q,
Work done (W) by the electrostaticforce is independent of the path.
Therefore, work done during the process is1.27 J.