Question

The electric field in a region of space is given by $\overrightarrow{E}=5\hat{i}+2\hat{j}{\text{NC}}^{-1}$. The electric flux due to this field through an area $2{\text{m}}^2$ lying in the $yz$- plane in S.I units is

• A. $10\sqrt{2}$
• B. $10$
• C. $20\sqrt{2}$
• D. $20$

Answer 1

The correct option is B $10$

Given,

$\overrightarrow{E}=5\hat{i}+2\hat{j}\overrightarrow{A}=2{\text{m}}^2\hat{i}$

Since the given surface is on $yz$-plane its normal will be along $x$ axis.

$\varphi =\oint \overrightarrow{E}.\overrightarrow{A}$

$=(5\hat{i}+2\hat{j}).\left(2\hat{i}\right)$

$=10{\text{NC}}^{-1}{\text{m}}^2$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, (b) is the correct answer.