A ray of light falls on a transparent glass slab of refractive index 1.52. If the reflected ray and refracted ray are mutually perpendicular, what is the angle of incidence?

Explanation

`2i + 90 + r = 180 + i`
`i + r =90 (r = 90 -i)`
`(sin i )/( sin r) = 1 52`
`sin r = sin (90-i)`
`= (BC)/(BA) = cos i`
`tan i 1. 52`
`i = tan ^(-1) (1. 52) = 56.65 ^(@)`
`r = 33. 35 ^(@)`