Electrostatics Question 12
Question 12 - 2024 (29 Jan Shift 2)
An electric field is given by $(6 \hat{i}+5 \hat{j}+3 \hat{k}) N / C$. The electric flux through a surface area $30 \hat{\mathrm{i}} \mathrm{m}^{2}$ lying in YZplane (in SI unit) is :
(1) 90
(2) 150
(3) 180
(4) 60
Show Answer
Answer: (3)
$\overrightarrow{\mathrm{E}}=6 \hat{\mathrm{i}}+5 \hat{\mathrm{j}}+3 \hat{\mathrm{k}}$
$\overrightarrow{\mathrm{A}}=30 \hat{\mathrm{i}}$
$\phi=\overrightarrow{\mathrm{E}} \cdot \overrightarrow{\mathrm{A}}$
$\phi=(6 \hat{\mathrm{i}}+5 \hat{\mathrm{j}}+3 \hat{\mathrm{k}}) \cdot(30 \hat{\mathrm{i}})$
$\phi=6 \times 30=180$
