Q. The maximum field intensity on the axis of a uniformly charged ring of charge $q$ and radius $R$ will be
A) $\frac{1}{4\pi\varepsilon_{0}}.\frac{q}{3\sqrt{3R^{2}}}$
B) $\frac{1}{4\pi\varepsilon_{0}}.\frac{2q}{3R^{2}}$
C) $\frac{1}{4\pi\varepsilon_{0}}.\frac{2q}{3\sqrt{3R^{2}}}$
D) $\frac{1}{4\pi\varepsilon_{0}}.\frac{3q}{3\sqrt{3R^{2}}}$
Explanation
(c) For a ring $E = \frac{1}{4\pi\varepsilon_{0}}.\frac{qx}{{(x}^{2} + R^{2})\ }$ and $E$ is maximum when
$x = \frac{R}{\sqrt{2}}\ $
$\Rightarrow \ \ \ \ E_{\max} = \frac{1}{4\pi\varepsilon_{0}}.\frac{2q}{3\sqrt{3}.R^{2}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.