
The electric field on two sides of a large charged plate is shown in Fig. The charge density on the plate in…

Solution

From the figure it is clear that the plate is placed in an external electric field. Let the electric field due to the plate is \(\mathrm{E}\) and \(\mathrm{E}_{0}\) be the external electric field.
\(\begin{array}{l}
\therefore \mathrm{E}_{0}+\mathrm{E}=12 \mathrm{Vm}^{-1} \\
\mathrm{E}_{0}-\mathrm{E}=8 \mathrm{Vm}^{-1}
\end{array}\)
Solving equation, \(\mathrm{E}=2 \mathrm{Vm}^{-1}\) and
\(\mathrm{E}_{0}=10 \mathrm{Vm}^{-1}\)
Now, electric field due to plate \(=\frac{\sigma}{2 \varepsilon_{0}}=2\)
\(\therefore \sigma=4 \varepsilon_{0}\)
Asked in: JEE Mains - Electrostatics - Chapter Test