Question

In a region of space, the electric field is given by $\vec{E}=8 \hat{ i }+4 \hat{ j }+3 \hat{k}$. The electric flux through a surface of area of 100 units in $x-y$ plane is

• A. 800 units
• B. 300 units
• C. 400 units
• D. 1500 units

Answer 1

Answer: (B)

Here, $\vec{E}=8 \hat{ i }+4 \hat{ j }+3 \hat{ k }$
$\vec{S}=100 \hat{k}$
(direction of the area is perpendicular to $x-y$ plane)
$\phi=\vec{E} \cdot \vec{S}=(8 \hat{ i }+4 \hat{ j }+3 \hat{ k }) \cdot 100 \hat{ k }$
$=300$ units