Which of the following correctly represents the variation of electric potential (V) of a charged spherical conductor of radius (R) with radial distance (r) from the centre?
(A)(see structure)
(B)(see structure)
(C)(see structure)✓ Correct
(D)(see structure)
Answer: (C)
Solution
Inside a charged conducting sphere the field is zero, so no work is needed to move a charge and the potential stays constant at its surface value RkQ right up to r=R. Outside the sphere the charge behaves as if concentrated at the centre, giving V=rkQ, which falls off hyperbolically with distance and joins the constant inner value continuously at the surface. The variation that is flat for r<R and then decreases as 1/r for r>R represents this behaviour.
JEE Main · 2023 · 31 Jan 2023 · Shift 1 · Single correct option