Q.
Three infinitely long charge sheets are placed as shown in figure. The electric field at point $P$ is
A) $\frac{2\sigma}{\varepsilon_{0}}\widehat{\mathbf{k}}$
B) $- \frac{2\sigma}{\varepsilon_{0}}\widehat{\mathbf{k}}$
C) $\frac{4\sigma}{\varepsilon_{0}}\widehat{\mathbf{k}}$
D) $- \frac{4\sigma}{\varepsilon_{0}}\widehat{\mathbf{k}}$
Explanation
(b) All the three plates will produce electric field at $P$ along negative $z$-axis. Hence,
$\mathbf{E}_{p} = \left\lbrack \frac{\sigma}{2\varepsilon_{0}} + \frac{2\sigma}{2\varepsilon_{0}} + \frac{\sigma}{2\varepsilon_{0}} \right\rbrack\left( - \widehat{\mathbf{k}} \right)$
$= - \frac{2\sigma}{\varepsilon_{0}}\widehat{\mathbf{k}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.