Question

Define

1. rigidity
2. compressibility
3. density and
4. fluidity

Answer 1

i) Rigidity:

• It is defined as the property of a substance in which the shape of the substance does not change due to an external force.
• Solid substances are rigid and hard.
• For example, table, chair, fan, etc.
• Rigidity gives the perfect shape to solids, the particles in the solid are tightly packed.
• Solid does not get deformed easily by applying extra pressure.

ii) Compressibility:

• It is defined as the ability of a substance to reduce the volume when pressure is applied.
• Gases are highly compressible in nature.
• With a lot of space between particles, a gas can be compressed to a higher extent.
• Solids have the least compressibility and liquids have little compressibility because of the least space between their particles.

iii) Density:

• It is defined as the mass per unit volume.
• Density = $\frac{\mathrm{Mass}}{\mathrm{Volume}}$
• It is denoted by $\rho$(rho).
• The density of solid is highest, then comes liquid, and last comes the gases.

iv) Fluidity:

• The ability of a substance to flow is called fluidity.
• The less force of attraction and more space between particles makes the liquid and gas flow easily.
• Fluidity is not observed in solids.