Correct Answer: D
Solution :
Total internal reflection is an optical phenomenon that occurs when light is refracted at a medium boundary enough to send it backwards, effectively reflecting all of the light. The critical angle is the minimum angle of incidence at which total internal reflection occurs. The critical angle for diamond is about\[24.4{}^\circ ,\] which means that light is much more likely to be internally reflected within a diamond. Diamonds for jewelry etc, are cut to take advantage of this, in particular the brilliant cut is designed to achieve high total reflection of light entering the diamond and high dispersion of the reflected light. Hence, a well cut diamond appears bright because of total internal reflection.
