When sun ray is incident at an angle `37^(@)` on the water surface, the reflected ray gets completely plane polarised. Find the angle of refraction and refractive index of water.

Explanation

According to question, angle of incidence
`=(90^(@) - 37^(@)) = 53^(@)`
`therefore` Angle of polarisation, `i_(p) = 53^(@)`
Now, `i_(p) + r = 90^(@) " " or, " i " = 90^(@) - i_(p) or," i " = 90^(@) - 53^(@) = 37^(@)`
According to Brewster's law, refractive index of water,
` mu = tan i_(p) = tan53^(@) = 1.327`