Question

A negative charge is moved from point A to point B along an equipotential surface. Which of the following statements must be true for this case? A) The negative charge performs work in moving from point A to point B. B) Work is required to move the negative charge from point A to point B. C) No work is required to move the negative charge from point A to point B. D) The work done on the charge depends on the distance between A and B. E) Work is done in moving the negative charge from point A to point B.

Answer 1

Answer:

C) No work is required to move the negative charge from point A to point B.

Explanation:

An equipotential surface is defined as a surface connecting all the points at the same potential.

Therefore, when a charge moves along an equipotential surface, it moves between points at same potential.

The work done when moving a charge is given by

$W=q\Delta V$

where

q is the charge

$\Delta V$ is the potential difference between the initial and final point of motion of the charge

However, the charge in this problem moves along an equipotential surface: this means that the potential does not change, so

$\Delta V=0$

And so, the work done is also zero.