A ray of light incident at an angle \(\theta\) in a rectangular prism grazes the surface of the prism on emerging from the prism. Determine the value of the angle. [Absolute refractive index of the material of the prism is 1.5]

  • A 41.8°
  • B 48.2°
  • C 60.8°
  • D 90.0°
waec 2017physics

The correct answer is A. 41.8°

\(\eta = \frac{1}{sin\theta}\)

\(1.5 = \frac{1}{sin\theta}\)

\(sin\theta = \frac{1}{1.5} = 0.667\)

\(\theta = sin^{-1}(0.667) = 41.835°\)

\(\approxeq 41.8°\)

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