Question

A charge is rotated in a circle of radius $r$ around a central charge. The work done is:

• A. Zero
• B. $qV$
• C. $V/q$
• D. $2\pi r q$

Hint:

A circular path around a point charge is an equipotential surface; no work is done moving along it.

Answer 1

The Correct Option is A

Step 1: Concept
Work done $W = q \Delta V$.
Step 2: Analysis
Potential $V = \frac{1}{4\pi\epsilon_{0}}\frac{q}{r}$. In a circular path around a central charge, the distance $r$ is constant.
Step 3: Conclusion
Since the potential is the same at all points on the circle, $\Delta V = 0$, so $W = 0$.
Final Answer: (A)