Question

Which of the following is/are correct about the point defects?

• A. In Frenkel defect, the dielectric constant of solid increases
• B. In Schottky defect, the density of solid decreases
• C. In Frenkel defect, the density of solid decreases
• D. In Shcottky defect, the dielectric constant of solid increases

Answer 1

Answer: (A), (B)

In Schottky defect, the density of solid decreases
In Frenkel defect, the dielectric constant of solid increases

(A) Frenkel defect tends to increase the dielectric constant of the crystal because of presence of the ions in interstitial sites.

(B) In Schottky defects an equal number of cations and anions are missing from the interstitial sites and form vacancy or hole and thus density decreases due to these missing cation and anions.

(C) In Frenkel defect in which an tom is displaced from its' lattice position to an interstitial site creating a vacancy at the original site and interstitial defect at the new location. The density do not change as it involves only migration of ions within the crystals preserving both volume and mass.

(D) In Schottky defect dielectric constant of solid do not change.

Answer: $A,B$