Question

The electric potential at the centre of two concentric half rings of radii $R_1$ and $R_2$, having same linear charge density $\lambda$ is :

• A. $\frac{2 \lambda}{\epsilon_0}$
• B. $\frac{\lambda}{2 \epsilon_0}$
• C. $\frac{\lambda}{4 \epsilon_0}$
• D. $\frac{\lambda}{\epsilon_0}$

Answer 1

Answer: (B)

Potential at centre
$ V=\frac{\left(\lambda \cdot \pi R_2\right)}{4 \pi \varepsilon_0 R_2}+\frac{\left(\lambda \cdot \pi R_1\right)}{4 \pi \varepsilon_0 R_1} $
$=\frac{\lambda}{2 \varepsilon_0}$