Question

A ray of light is incident at an angle of, incidence $ 60{}^\circ $ from air to liquid. What is the 1 ratio of width from air to liquid if angle of refraction is $ 45{}^\circ $ ?

• A. $ \frac{\sqrt{2}}{3} $
• B. $ \sqrt{\frac{3}{2}} $
• C. $ \sqrt{\frac{2}{3}} $
• D. $ \frac{1}{\sqrt{2}} $

Answer 1

Answer: (D)

$ \frac{\text{Width of incident wavefront}}{\text{Width of refracted wavefront}}=\frac{\cos i}{\cos r} $ $ =\frac{\cos 60{}^\circ }{\cos 45{}^\circ }=\frac{1/2}{1/\sqrt{2}} $ $ =\frac{1}{\sqrt{2}} $