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JAMB Physics 1992 Question 28

Question 28

Refraction of Light

The speed of light in air is 3 × 108 m s−1. What is the speed in glass with a refractive index of 1.50?

  1. A.1.5 × 108 m s−1
  2. B.3.0 × 108 m s−1
  3. C.2.0 × 108 m s−1
  4. D.6.0 × 108 m s−1
Show the answer and explanation

Answer: C (2.0 × 108 m s−1)

Explanation

n = speed in air ÷ speed in glass, so v = 3 × 108 ÷ 1.5 = 2.0 × 108 m s−1.