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AP EAMCET · PHYSICS · Ray Optics

A beam of light is incident from air on the surface of a liquid. The angle of incidence is \(\theta\) and the angle of refraction is \(\alpha\). If the critical angle for liquid when surrounded by air is \(\theta_c\) then \(\sin \theta_c\) is

  1. A \(\frac{\sin \alpha}{\sin \theta}\)
  2. B \(\sin \alpha \times \sin \theta\)
  3. C \(\frac{\sin \theta}{\sin \alpha}\)
  4. D \(\frac{\sin \alpha}{\cos \theta}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{\sin \alpha}{\sin \theta}\)

Step-by-step Solution

Detailed explanation

Refractive index of liquid with respect to air, \(n_{l a}=\frac{\sin i}{\sin r}\) Here, \(i=\theta\) and \(r=\alpha\) So, refractive index of liquid with respect to air, \(n_{l a}=\frac{\sin \theta}{\sin \alpha}\) Now, if \(\theta_c=\) angle of critical incidence for liquid…