For the given incident ray as shown in figure, the condition of total internal reflection of the ray will be satisfied if the refractive index of block will be: [AIPMT 2002] |
A) \[\frac{\sqrt{3}+1}{2}\]
B) \[\frac{\sqrt{2}+1}{2}\]
C) \[\sqrt{\frac{3}{2}}\]
D) \[\sqrt{\frac{7}{6}}\]
Correct Answer: C
Solution :
Key Idea: For total internal reflection angle of incidence should be greater than critical angle. |
For total internal reflection to take place, angle of incidence > critical angle |
i.e., |
or |
or |
but |
and from figure, |
So, |
i.e., (i) |
From Snell's law, |
Thus Eq. (i) becomes |
or |
or |
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