A ray of light from denser medium strikes a rarer medium at angle of incidence i. The reflected and refracted rays make an angle of 90° with each other. The angle of reflection and refraction are r and r' respectively. The critical angle is ___ .
(A) sin–1 (tan i)
(B) tan–1 (tan r)
(C) tan–1 (sin i)
(D) sin–1 (tan r)
The correct option is (D) sin–1 (tan r).
Explanation:
from figure, as angle between reflected & refracted ray is 90°,
