Question

Define line defect.

Answer 1

Hint: Think about the difference between a real crystal and a perfect crystal. What do you mean by the word ‘defect’? Think about irregularity in crystals.

Complete step by step answer:
-A perfect crystal has all atoms or constituent particles arranged in a precise geometric order over a long range whereas in a real crystal, there is always some fault or imperfection in the formation of the crystal lattice. The latter mainly occurs in case of big crystals.
-A defect is the term used to describe the irregularity in the pattern of arrangement of repeating units. There are two types of defects, one is point defect and another one is line defect.
-A point defect is a defect which arises due to a fault produced in the arrangement of a lattice point or a constituent particle in a crystalline solid.
- A line defect is a type of crystal defect in which there is irregularity in a complete line, or a row of lattice points of constituent particles in a crystalline solid.

-It can also be defined as a line along which an entire row of atoms or constituent particles are arranged anomalously.
- In a line defect, a whole slab of atoms or constituent particles gets shifted. This is known as dislocation. So, line defects are also known as dislocations.
-Line defects have the potential to weaken or strengthen a solid.

Note: Please don’t get confused between point defect and line defects. As their name suggests, point defect is the one in which lattice points are missing or extra or displaced. But, in line defect, a whole line of lattice points gets dislocated.