Q 12-01-073JEE MainJEE Main 2023 (31 Jan, Shift 1)Medium
Expression for an electric field is given by $\vec E=4000x^2\hat i\ \text{V m}^{-1}$. The electric flux through the cube of side $20\ \text{cm}$ when placed in electric field (as shown in the figure) is ______ V cm.
Numerical value type. Enter your answer.
Answer: 640
$\vec E$ is along $x$, so only the faces $x=0$ and $x=0.2\ \text{m}$ carry flux.
At $x=0$: $E=0$. At $x=0.2$: $E=4000\times0.04=160\ \text{V m}^{-1}$.
$$\phi=160\times(0.2)^2=6.4\ \text{V m}=640\ \text{V cm}$$
Solution by Sreeraj P, M.Sc Physics