question_answer

A ray of light from a denser medium strikes a rare medium as shown in figure. The reflected and refracted rays make an angle of \[90{}^\circ \] with each other. The angles of reflection and refraction are r and r. The critical angle would be:

A)  \[{{\sin }^{-1}}(\tan \,r)\]

B)                         \[{{\tan }^{-1}}(sin\,i)\]

C)  \[{{\sin }^{-1}}(\tan \,i)\]            

D)         \[{{\tan }^{-1}}(\sin \,r)\]