Question

A surface $ds=10\hat{j}$ is kept in an electric field $\overrightarrow{E}=2\hat{i}+4\hat{j}+7\hat{k}$. How much electric flux will come out through the surface?

• A. $40$ unit
• B. $50$ unit
• C. $30$unit
• D. $20$ unit

Answer 1

Answer: (A)

$40$ unit

$\varphi =\overrightarrow{E}.\overrightarrow{ds}$

$=(2\hat{i}+4\hat{j}+7\hat{k}).\left(10\hat{j}\right)$

$=4\times 10$

$=40units$