Consider a uniform electric field `E=3xx10^(3)hat(i)` N/C.
What is the flux the square of 10 cm on side , if the normal to its plane makes an angle `60^(@)` with the X-axis ?

Explanation

Here, `E=3xx10^(3)hat(i)` N/C, i.e. field is along positive direction of X-axis.
Surface area, `S=(10" cm")^(2)=10^(-2)m^(2)`
When normal to the plane makes an angle of `60^(@)` with X-axis, then `theta=60^(@)`
`:.phi_(E)="ES"costheta=3xx10^(3)xx10^(-2)cos60^(@)`
`phi_(E)=30xx1/2=15"N-m"^(2)//C`