Question

The figure shows the equipotential contours due to three point charges. The labels on the contours are in Volts.

• A. The electric field at $e$ is directed normal to the $221.7\text{V}$ contour and away from the $312.1\text{V}$ contour
• B. A charge released from rest on one of these contours will not move along the contour
• C. Two of charges are positive and one is negative
• D. $–118.1\text{J}$ of work is done to move a charge of $1\text{Coulomb}$ from $d$ to $c$ along the contour

Answer 1

Answer: (A), (B)

The correct options are
A The electric field at $e$ is directed normal to the $221.7\text{V}$ contour and away from the $312.1\text{V}$ contour
B A charge released from rest on one of these contours will not move along the contour

(A) Electric field is directed perpendicular to equipotential surface and from high potential to low potential.
(B) Force on the charge is perpendicular to the equipotential.
(C) Because we have zero potential not at $\infty$, so charge can't be commented. Any combination may be possible.
(D) Work done on an equipotential line is zero.