Optics Question 446
Question: A ray of light is incident on a glass sphere of refractive index 3/2. What should be the angle of incidence so that the ray which enters the sphere does not come out of the sphere?
Options:
A) $ te{{n}^{-1}}(2/3) $
B) $ 60^{0} $
C) $ 90^{0} $
D) $ 30^{0} $
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Answer:
Correct Answer: C
Solution:
[c] $ \angle ABO=\angle OAB={\theta _{c}} $
$ \sin {\theta _{c}}=\frac{1}{\mu }=\frac{2}{3} $
Applying snell’s law at A $ \frac{\sin i}{\sin {\theta _{C}}}=\frac{3}{2} $
$ \sin i=( \frac{3}{2} )( \frac{2}{3} )=1 $ Or $ i=90{}^\circ $
