A closed cylinder is placed in uniform electric field.Find electric flux passing through cylinder.

Explanation

Divide cylinder into three parts , two circular part `(a)` and `(b)` and one cylindrical surface `(c )`.
`phi = phi_(a) + phi_(b) + phi_(c )`
`= int_(a) vec(E ) . d vec(S) + int_(b) vec(E) . d vec(S) + int _(c ) vec(E) . d vec(S)`
`= int EdS cos 0 + int EdS cos 180^(@) + int EdS cos 90^(@)`
`= E S - E S + 0 = 0`