A ray of light form a denser medium strikes a rarer medium at angle of incidence i The reflected - Physics - Waves

Question

A ray of light form a denser medium strikes a rarer medium at angle
of incidence i The reflected and refracted rays make an angle of 90
degrees with each other The angle of reflection and refraction are
r and r' resp the critical angle is?

Pratyay Ghosh · Accepted Answer

For the reflection,
i=r
The reflected and refracted rays make angle,
1800-(r+r')=900⇒r+r'=900⇒r'=900-r=900-i
So,
μsini=sin900-i⇒μsini=cosi⇒μ=1tani
Critical angle,
θc=sin-11μ⇒θc=sin-1tani

A ray of light form a denser medium strikes a rarer medium at angle of incidence i. The reflected and refracted rays make an angle of 90 degrees with each other. The angle of reflection and refraction are r and r' resp. the critical angle is?