Question

A flat circular disk of radius "a" is placed inside a uniform external electric field E' pointing in positive z direction. calculate the net electric flux through the disk.

Answer 1

Assuming the plane of the disk is horizontal

$\phi=\int\>E.dA$

Since electric field is uniform

$\phi=EA\>Cos\>\theta$

$\theta=0°$

$\phi=EA$

But $A=\pi\>a^2$

$\phi=\pi\>Ea^2$

Where $E=$ Electric field

$\phi=$ Electric flux