A) \[n<\frac{1}{\sqrt{2}}\]
B) \[n>\sqrt{2}\]
C) \[n>\frac{1}{\sqrt{2}}\]
D) \[n<\sqrt{2}\]
Correct Answer: B
Solution :
For total internal reflection from glass-air interface, critical angle C must be less than angle of incidence. i.e., \[C<i\] or \[C<45{}^\circ \] \[(\because \angle i=45{}^\circ )\] But, \[n=\frac{1}{\sin C}\] \[\Rightarrow \] \[C={{\sin }^{-1}}\left( \frac{1}{n} \right)\] \[\Rightarrow \] \[\frac{1}{n}<\sin {{45}^{o}}\] \[\Rightarrow \] \[n>\frac{1}{\sin {{45}^{o}}}\] \[\Rightarrow \] \[n>\frac{1}{(1/\sqrt{2})}\] \[\Rightarrow \] \[n>\sqrt{2}\]You need to login to perform this action.
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