The electric field in a region is given by `vec (E ) = (E_(0))/(a) x hat(i)`. Find the electric flux passing through a cubical volume bounded by the surfaces `x = 0 , x = a , y = 0 , y = a , z = 0` and `z = a`.

Explanation

On four faces , electric field and area are perpendicular , hence no flux . One face is at origin i.e. `x = 0 , E = 0` , no flux. On the sixth face , `x = a`
`phi = vec (E ) . Vec(S ) = E_(0) hat(i) . a^(2) hat(i) = E_(0) a^(2)`