Crystal defects or imperfections | Crystal physics | தமிழில் | Anusuya A

Описание: Crystal defects or imperfections | Crystal physics | தமிழில் | Anusuya A

Crystal defects oneword(mcqs) | Anusuya A

1. Which of the following is a point defect in crystals?
a) Edge dislocation
b) Interstitialcies
c) Grain boundaries
d) Cracks

Answer: b
Explanation: Crystal defects are classified as point defects, line defects, and boundary defects. Point defects include vacancies, impurities, interstitialcies, and electronic defects.

2. The defect that occurs due to a displacement of an ion is known as __________
a) Vacancy defect
b) Schottky defect
c) Frankel defect
d) Interstitial defect

Answer: c
Explanation: Frankel defect occurs due to a displacement of an ion from the crystal lattice. It is related to the interstitial defect, where an ion simply occupies a position between regular atoms.

3._______ occurs when a foreign substance replaces an atom in a crystal.
a) Vacancy defect
b) Substitutional impurity
c) Frankel defect
d) Interstitial impurity

Answer: b
Explanation: A substitutional impurity occurs due to the occupation of a foreign atom in place of an atom in a crystal. On the other hand, interstitial impurities occur when a regular atom occupies a random space in the crystal lattice.

4.A disturbance in a region between two ideal parts of a crystal is known as ________
a) Boundary defect
b) Point defect
c) Line defect
d) Volume defect

Answer: c
Explanation: Line defect is regarded as a disturbed region between two perfect parts of a crystal. They may be of either edge dislocation type or screw dislocation.

5. In screw dislocation, the Burger’s vector lies _________ to the dislocation line.
a) Perpendicular
b) Parallel
c) At an angle
d) Sideways

Answer: b
Explanation: The Burger’s vector in screw dislocation lies parallel to the dislocation line along the axis of a line of atoms in the same plane. On the other hand, it lies at an angle for edge dislocation.

6.  What are one-dimensional defects?
a) Boundary defect
b) Point defect
c) Line defect
d) Volume defect

Answer: c
Explanation: When compared geometrically, line defects are seen as one-dimensional defects. Line defects are also known as dislocations, with common types as edge and screw dislocations.

7.What are two-dimensional defects?
a) Boundary defect
b) Point defect
c) Line defect
d) Volume defect

Answer: a
Explanation: The defects that occur on the surface of a material are known as surface or boundary defects. Geometrically, they are regarded as two-dimensional defects.