passwella.
Menu

JAMB Physics 1987 Question 36

Question 36

Refraction of Light

A ray of light is incident at an angle of 30° on one top surface of a parallel-sided glass block of refractive index 1.5. The ray finally emerges from the lower surface. What is the angular deviation of the emergent ray?

  1. A.60°
  2. B.39°
  3. C.28°
  4. D.0°.
Show the answer and explanation

Answer: D (0°.)

Explanation

With parallel faces the ray bends one way going in and back the same amount coming out, so it emerges parallel to its original direction: zero deviation (only a sideways shift).