Equation 1 shows that in the present case where n₁ < n₂ (air glass interface), the amplitude coefficient of reflection for the s wave (perpendicular component) is negative, indicating that the reflected and the incident wave are out of phase. The magnitude of reflection coefficient for this particular components increases with the increasing angle of incidence going to the value of 1 at (fig 3) .

Using the snall's law, equation 3 can be re-written as

                ..........................(5)

This will be positive and decrease with the angle of incidence for

                

or equivalently

                 ......................................(6)