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TS EAMCET · Physics · Ray Optics

A ray of light is incident on the hypotenuse of a right-angled prism after travelling parallel to the base inside the prism. If \(\mu\) is the refractive index of the material of the prism, the maximum value of the base angle for which light is totally reflected from the hypotenuse is

  1. A \(\sin ^{-1}\left(\frac{1}{\mu}\right)\)
  2. B \(\tan ^{-1}\left(\frac{1}{\mu}\right)\)
  3. C \(\sin ^{-1}\left(\frac{\mu-1}{\mu}\right)\)
  4. D \(\cos ^{-1}\left(\frac{1}{\mu}\right)\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\cos ^{-1}\left(\frac{1}{\mu}\right)\)

Step-by-step Solution

Detailed explanation

For total internal reflection, \(\mu=\frac{1}{\sin C}\) \(\mu=\frac{1}{\sin \left(90^{\circ}-\theta\right)}\) \(\mu=\frac{1}{\cos \theta} \Rightarrow \cos \theta=\frac{1}{\mu}\) \(\theta=\cos ^{-1}\left(\frac{1}{\mu}\right)\)
From TS EAMCET
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