Question Detail
Question
A light ray is directed at a vertical face of a glass cube. The angle of incidence at the vertical face is 39° and the angle of refraction is 25° as shown in the diagram. Calculate the refractive index of the glass, if the refractive index of air is 1.
Correct Answer
Option B is the correct answer.
Detailed Explanation
Using Snell's law: n_air sin i = n_glass sin r. n_air = 1. So n_glass = sin i / sin r = sin 39° / sin 25° = 0.6293 / 0.4226 = 1.489. The closest option is 1.489. Option A. Let's recheck the values. sin 39 = 0.6293, sin 25 = 0.4226. Ratio = 1.489. So the answer is A.
Hint
Snell's law: n1 sin i = n2 sin r.