Question

The following is not a function of an impurity present in a crystal
A) Establishing thermal equilibrium
B) Having tendency to diffuse
C) Contributing to scattering
D) Introducing new electronic energy levels

Answer 1

Hint: Impurity in crystal gives rise to another defect in the crystal lattice. This defect has given certain new properties to the crystal lattice. This impurity occupies the vacant site or the interstitial space in the crystal.

Complete Step by Step Answer:
Impurity means presence of any different atom or ion in a crystal from their constituent atoms or ions. When a different atom occupies the position of the constituent atom of any crystal or it occupies the intestinal space of the crystal this impurity defect arises. This impurity defect causes many changes in the property of the crystal as follows:
- These impurities in the crystal have a high tendency to diffuse in the crystal.
- When the impurity occupies the position of the constituent atom of the crystal it helps to scatter light more than the constituent atoms.
- Due to impurity the electron absorbs light and goes to a higher energy level. Thus it introduces new energy levels.
- Impurity defect does not establish thermal equilibrium in the crystal lattice.
Thus the correct option is A.

Note: To produce large crystals impurities must be introduced. A crystal with high impurity becomes similar to an alloy which is formed by the mixing of several metals together.