Optics Question 98
Question: The refractive index of the material of the prism and liquid are 1.56 and 1.32 respectively. What will be the value of q for the following refraction
[BHU 2003; CPMT 2004]
Options:
A) $ \sin \theta \ge \frac{13}{11} $
B) $ \sin \theta \ge \frac{11}{13} $
C) $ \sin \theta \ge \frac{\sqrt{3}}{2} $
D) $ \sin \theta \ge \frac{1}{\sqrt{2}} $
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Answer:
Correct Answer: B
Solution:
For total internal reflection from surface $ BC $
$ \theta \ge C\Rightarrow \sin \theta \ge \sin C $
$ \Rightarrow \sin \theta \ge ( \frac{1}{ _{l}{\mu _{g}}} ) $
$ \Rightarrow $ $ \sin \theta \ge ( \frac{{\mu _{Liquid}}}{{\mu _{Prism}}} ) $
$ \sin \theta \ge ( \frac{1.32}{1.56} )\Rightarrow \sin \theta \ge \frac{11}{13} $
