Minimum refractive index

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written 8.8 years ago by

teamques10 ★ 69k

• modified 8.8 years ago

A 45° - 45° - 90° prism is immersed in alcohol (n = 1.45). What is the minimum refractive index the prism must have if a ray incident normally on one of the short faces is to be totally reflected at the long face of a prism?

Mumbai University > Electronics Engineering > Sem7 > Optical Fiber Communication

Marks: 5M

Year: May 2012

optical fiber communication

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written 8.8 years ago by

teamques10 ★ 69k

Given:

$θ_c$ = 45° $n_1$ = 1.45

To find: refractive index $n_2$

Solution:

$θ_c= sin^{-1} \frac{n_2}{n_1} \\ \; \\ sin^{-1} \frac{n_2}{n_1} = 45° \\ \; \\ \frac{n_2}{n_1} = sin 45 = 0.707 \\ \; \\ n_2 = 1.45 * 0.707 \\ \; \\ = 1.025$

$n_2$ = Minimum refractive index= 1.025

$\boxed{Minimum \ \ refractive\ \ index(n_2)= 1.025}$

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