Question

what is the minimum angle to undergo total internal reflection for a ray falls on diamond?

Answer 1

42 degree ..........

Answer 2

Total internal reflection is the main cause of the brilliance of diamonds. The refractive index of diamond with respect to air is 2.42. Its critical angle is 24.41o. When light enters diamond from any face at an angle greater than 24.41o it undergoes total internal reflection. By cutting the diamond suitably, multiple internal reflections can be made to occur.