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MHT CET · Physics · Ray Optics

If angle of incidence is twice the angle of refraction in a medium of refractive index \(\mu\), then angle of incidence is

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

Answer & Solution

Correct Answer

(A) \(2 \cos ^{-1} \frac{\mu}{2}\)

Step-by-step Solution

Detailed explanation

According to Snell's law Refractive index, \(\mu=\frac{\sin i}{\sin r}\)
Given \(i=2 r\)
\(\therefore\) \(
\mu=\frac{\sin 2 r}{\sin r}
\)
or \(\mu=\frac{2 \sin r \cos r}{\sin r}\)
or \(\quad \cos ^{-1} \frac{\mu}{2}=r\)
\(
i=2 \cos ^{-1} \frac{\mu}{2}
\)