(i) State Brewster's law. (ii) An unpolarised light is incident at angle of polarisation on a reflector. Determine the angle between the reflected and the transmitted rays.

Explanation

From Brewster's law,
`mu = tan i_(p) [i_(p)` = angle of polarisation]
Again, `mu = (sin i_(p))/(sin r) or, tan i_(p) = (sin i_(p))/(sin r),`
or, `sin r = cos i_(p) = sin (90^(@) - i_(p))`
or, r =`90^(@) - i_(p)` or, `i_(p) + r = 90^(@)`
From the figure, the angle between the reflected and the transmitted rays
`= 180^(@) - (i_(p) + r ) = 180^(@) - 90^(@) = 90^(@)`