Question

Charge Q is distributed non-uniformly over a ring of radius R. P is a point on the axis of ring at a distance $\sqrt{3}R$ from its centre. Which of the following is a wrong statement.

• A. Potential at P is $\frac{2K_q}{R}$
• B. Magnitude of electric field at P may be greater than $\frac{\sqrt{3}KQ}{8R^2}$
• C. Magnitude of electric field at P must be equal to $\frac{\sqrt{3}KQ}{8R^2}$
• D. Magnitude of electric field at P may be less than $\frac{\sqrt{3}KQ}{8R^2}$

Answer 1

The correct option is A Potential at P is $\frac{2K_q}{R}$

Charge $=Q$

radius $=R$

$P$ at point on the axis of ring at a distance $=\sqrt{3}R$ from its centre

$d=\sqrt{R^2+{3R}^2}=2R$

$V=\frac{K_q}{2R}+\frac{3K_q}{2R}=\frac{2K_q}{R}$.