question_answer

A ray of light from a denser medium strikes ararer medium at an angle of incidence i. Thereflected and refracted rays make an angle of\[t=\infty \]/2 with each other. If the angles ofreflection .end refraction are r and r, thenthe critical angle will be

A) \[\frac{{{e}^{1/2}}}{{{e}^{1/2}}-1}\]                       

B)  \[\frac{{{e}^{2}}}{{{e}^{2}}-1}\]

C) \[1-{{e}^{-1}}\]                

D) \[{{e}^{-1}}\]

Correct Answer: C

Solution :

                Refractive index \[{{r}^{7/2}}\] But      \[{{r}^{5/2}}\] or  \[{{r}^{3/2}}\]                 \[l\] \[\frac{l}{L-l}\]   \[\frac{L}{l}\]                 or            \[\frac{l}{L}\] or            \[\frac{lL}{L+l}\]