The potential of a charged spherical conductor of radius r is 20 V. The potential at a point \( \displaystyle\frac{r}{4} \) from its center is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 20 V
In electrostatic equilibrium the electric field inside a charged conductor is zero. No work is done in moving a charge between two points inside it, so the potential is the same at every point inside and equal to the potential on the surface.
The point at \( r/4 \) from the centre lies inside the sphere, so its potential is 20 V.
NCERT (2026-27):
Electrostatics of Conductors – “… 4. Electrostatic potential is constant throughout the volume of the conductor and has the same value (as inside) on its surface”