Question

A half ring of radius R is charged with a linear charged density $\lambda$. The field at the centre is

• A. 0
• B. $\frac{k\lambda }{R}$
• C. $\frac{2k\lambda }{R}$
• D. $\frac{k\pi \lambda }{R}$

Answer 1

The correct option is C

$\frac{2k\lambda }{R}$

$dl=Rd\theta dq=\lambda R\theta dE=\frac{K.\left(dq\right)}{R^2}E={\int }_{-\frac{\pi }{2}}^{\frac{\pi }{2}}K.\frac{dq}{R^2}cos\theta =\frac{2K\lambda }{R}$