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AP EAMCET · PHYSICS · Ray Optics

In an optical fibre, core and cladding were made with materials of refractive indices 1.5 and 1.414 respectively. To observe total internal reflection, what will be the range of incident angle with the axis of optical fibre?

  1. A \(0^{\circ}-60^{\circ}\)
  2. B \(0-48^{\circ}\)
  3. C \(0^{\circ}-30^{\circ}\)
  4. D \(0^{\circ}-82^{\circ}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(0^{\circ}-30^{\circ}\)

Step-by-step Solution

Detailed explanation

The range of incident angle \(\sin \theta=\frac{\sqrt{\mu_1^2-\mu_2^2}}{\mu_0}\) \(\theta=\sin ^{-1} \sqrt{\left(\mu_1\right)^2-\left(\mu_2\right)^2} \quad\left[\right.\) for air \(\left.\mu_0=1\right]\) \(\theta=\sin ^{-1} \sqrt{(1.5)^2-(1.414)^2}\) \(=\sin ^{-1}(0.5006)\)…