The refractive index of a material is 1.5. Calculate the critical angle at the glass-air interface
Answer Details
The critical angle is the angle of incidence at which the angle of refraction is 90 degrees. Using Snell's law, we can relate the critical angle to the refractive index. At the critical angle, the sine of the angle of refraction is 1, so we can write: sin(critical angle) = 1/n where n is the refractive index. Substituting n=1.5 gives: sin(critical angle) = 1/1.5 = 0.67 Taking the inverse sine of both sides gives: critical angle = sin-1(0.67) = 42o Therefore, the correct answer is 42o.