Two rays of light from a point below the surface of water are equally inclined...

JAMB 1985

Two rays of light from a point below the surface of water are equally inclined to each other at 60^o in water. What is the angle between the rays when they emerge into air? (Take the refractive index of water to be \(\frac{4}{3}\))

A. 41.8^o
B. 44.1^o
C. 60.0^o
D. 83.6^o
E. 120.0^o

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Correct Answer: Option D

Explanation

\(\frac{4}{3}\) = \(\frac{sin r_1}{sin 30}\) and \(\frac{4}{3}\) = \(\frac{sin r_2}{sin 30}\)

r₁ = 41.8^o and r₂ = 41.8^o

angle between them = r₁ + r₂

= 83.6^o

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