When light of a certain wavelength is incident on a plane surface of a material at a glancing angle `30^@`, the reflected light is found to be completely plane polarized Determine
Angle of refraction.

Explanation

a) Angle of incident light with the surface is `30^@` . The angle of incidence = `90^@-30^@ = 60^@`. Since reflected light is completely polarized, incidence takes place at polarizing angle of incidence `theta_p`
` therefore theta_p = 60^@ `
Using Brewster.s law
`mu tan theta_p = tan 60^@ rArr mu = sqrt3`
b) From snell.s law
`mu = (sin i)/(sin r) , therefore sqrt3 = (sin 60^@)/(sin r)`
or sin ` = (sqrt3)/(2) xx (1)/(sqrt3) = 1/2 , r = 30^@`