A ray of light falls on a transparent glass slab of refractive index `1.62`. If the reflected ray and the refracted rays are mutually perpendicular, what is the angle of refraction ?

Explanation

According to given problem : `r= 90^(@) + r' = 180 ^(@)` i.e, `r'= 90^(@) - r`
`implies r' = (90^(@) -i) [because anglei = angler]` and as according to Snell's law: `1` "sin"i = `mu` sinr'
sin I and `mu"sin"(90-i) implies "sin"i = mu"cos"i [because "sin"(90-i) = "cos"i`]
`implies "tan"i = mu implies i = tan^(-1)(1.62)= 58.3^(@)`