NCERT TEXTBOOK EXERCISES
Why are solid rigid
In solid, the particles are closely packed and the empty spaces between the particles are very small.Therefore solids are incompressible and they maintain their own shape when subjected to outside force.Hence ,solids are rigid.
Why do solids have definite volume?
The intermolecular forces between the particles in the solid state are very strong. Therefore, they are strongly held at fixed positions and particles cannot separate from one another. Hence, solids have a definite volume.
Classify the following as amorphous or crystalline solids:Naphthalene,Teflon,Polyurethane,Benoit acid,Potassium nitrate,Cellophane,Polyvinyl chloride,Fibre glass,Copper,Zinc sulphide
Solution:-
Amorphous solids:-Teflon, Polyurethane, Cellophane,Polyvinyl chloride, Fibre glass
Crystalline solids:-Naphthalene,Benoit acid,Potassium nitrate,Copper,Zinc sulphide.
Why is glass considered a supercooled liquid
Glass is an amorphous solid. Like liquids it has a tendency to flow, through very slowly. Moreover, glass is obtained when molten silicates are allowed to cool rapidly. Therefore, glass is considered as a supercooled liquid.
Solid A is very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it
Covalent or network solid like quartz (SiO2),SiC or C (diamond).
What type of solids are electrical conductors,malleable and ductile
Metallic solid
Give the significance of lattice point.
Lattice points represent the positions of the constituent particles (atoms,molecules or ions)in a crystal lattice.
What type of defect can arise when a solid is heated ?Which physical property is affected by it and in what way
Electronic imperfections
These defects affect electrical conductivity. It increases with rise in temperature.