If the electric field in a region of space is given by $\vec{E} = 4\hat{i}+\hat{j}+5\hat{k}$. The el

Question

If the electric field in a region of space is given by $\vec{E} = 4\hat{i}+\hat{j}+5\hat{k}$. The electric flux through of surface of area 20 units lying in the y-z plane is

Professor PC Thomas Classes · Answer

For a surface in y-z plane, area vector is along x-axis: $\vec{A} = 20\hat{i}$. Flux $\phi = \vec{E} \cdot \vec{A} = (4\hat{i}+\hat{j}+5\hat{k}) \cdot 20\hat{i} = 4 	imes 20 = 80$ units.