What is the work done in carrying a point charge from a point X to a point Y on an equipotential surface at a potential of 5 V?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Zero
An equipotential surface has the same potential at every point on it. The work done in carrying a charge q from one point to another equals q times the potential difference between them.
\( \begin{aligned} W &= q\,(V_Y-V_X) \\ &= q\,(5\,\mathrm{V}-5\,\mathrm{V}) \\ &= 0 \end{aligned} \)
The value 5 V of the potential does not matter. Only the potential difference between X and Y decides the work.
NCERT (2026-27):
Equipotential Surfaces – “An equipotential surface is a surface with a constant value of potential at all points on the surface.”
Equipotential Surfaces – “… the definition of an equipotential surface: there is no potential difference between any two points on the surface and no work is required to move a test charge on the surface.”