alleryCritical angle for diamond (n = 2.42):
A45°
B60°
C90°
DAbout 24.4°
Answer & Solution
Correct answer: D. About 24.4°
sin θ_c = 1/n = 1/2.42 ≈ 0.413. θ_c ≈ 24.4°.
Small θ_c means light easily gets trapped inside — multiple TIRs cause diamond's brilliance (light enters but takes many internal reflections before exiting toward viewer).
Keep practising Ray Optics
Browse all Ray Optics questions for JEE Advanced, or explore more Physics topics.
Related questions
Complete the lens formulaFind the property that does not match concave mirrorsRefraction — true or false?A ray enters a glass slab at 45°. Glass n = 1.5. Angle of refraction inside glass:For total internal reflection at glass-water interface (n_g = 1.5, n_w = 1.33), critical aFor object at 60 cm from convex lens of f = 20 cm, image is:Magnifying power of simple magnifier (image at near point):Refractive index of medium 1 w.r.t. medium 2 is n₁₂. Then: