Question

The brilliance of diamond is due to the internal reflection of light is slowed down and bent away from its original path because it strikes:
A.Tightly bound nucleus
B.The nucleus (center) of carbon atoms
C.Loosely held mobile electrons
D.Layers of carbon atoms

Answer 1

We must remember that the diamond is the solid form of the carbon having crystal structure. The diamond will not conduct the electricity. Because, the covalently bonded carbon atom in diamonds is arranged in tetrahedral manner. And it is an allotrope of carbon atoms which contain pure carbon atoms. And it has a closely packed structure with extra atoms present in the holes.

Complete answer:
The structure of diamond is a crystal like structure. Because here all the carbon atoms are arranged in a crystal structure manner and it is in solid form. The brilliance of diamond is due to the internal reflection of light being slowed down and bent away from its original path because it strikes a tightly bound nucleus. And the index of refraction of diamond is very high with critical angle of air – diamond is ${24.4^o}$. Therefore, the light is getting back out from the diamond. Hence, option (A) is correct.
The slowdown of reflection of light from the diamond is not because of the nucleus of the carbon atom. Hence, the option (B) is incorrect.
The mobile electrons are not held loosely in diamond. Therefore, it is not a reason for the slowdown and bent away from the original path. Hence, option (C) is incorrect.
The layers of carbon atoms do not depend on the reflection of diamond. Hence, the option (D) is incorrect.

Hence, option (A) is correct.

Note:
We need to know that the diamond has a high index of refraction and total internal reflection. According to the total internal reflection, it takes place, by the travelling of light from the higher optically denser medium to the lower optically denser medium. And the incident ray of light will be refracted at a specific angle of incidence and it will pass along the surface of water.