Question

What type of defect can arise when a solid is heated? Which physical property is affected by it and in what way?

Answer 1

Hint:Solid particles tend to be tightly packed in its lattice because of the force of attraction present between the particles. They have definite shape and definite volume. They are rigid and incompressible. The solid exhibits the dielectric properties such as piezoelectricity, pyroelectricity, ferroelectricity and antiferroelectricity.

Complete answer:
There are many types of imperfections present in the crystalline solid such as vacancy defect, line defect, surface defect or volume defect. Vacancy defect generally occurs when the atom gets missed from its original lattice site. It is a zero dimensional defect. It tends to create tension for the neighbouring atoms. In this defect we see the increase in the hardness of solid. This defect can be found in any crystalline solid. The substance who has the temperature above absolute zero temperature can have such vacancies thus causing vacancy effect. This vacancy effect occurs because of not allowing directional solidification during casting or when the temperature gets increased for processes such as heating or coating or during sputtering effect or presence of the residual tensile stress in it. So the defect arising on heating a solid is a vacancy defect. The physical property which is affected by vacancy effect is density.In vacancy defects the atoms get reduced from the structure due to which the mass of the substance gets reduced and as we know that density is directly proportional to mass so increase in vacancies decreases the density of the substance.

Note: The other effects of vacancy effect on the substance is that it increases the Young modulus of the substance but decreases its Bulk modulus. If the vacancies are in large amounts then the ductile property of substance decreases. It also changes the thermal resistivity and electrical resistivity of the substance.