Question

Define density and relative density.

Answer 1

Hint: In the measurement system, different materials have different densities. Density specifies how dense a material is. Some materials are denser while some are less dense. For the comparison between the densities of two different materials, relative density can be specified.

Complete step by step answer:
The density of a material is defined as the ratio of its mass per unit volume. It is also called the volumetric mass density, or the specific mass.
Mathematical expression for density:
$\text{Density = }\dfrac{\text{Mass}}{\text{Volume}}$
Or,
$\rho =\dfrac{M}{V}$
Where,
$\rho $ is the density
$M$ is the mass
$V$ is the volume
The density of a material can vary with the change in temperature and pressure. Increasing the amount of pressure on an object decreases the volume of the object resulting in increases in its density. Increase in the temperature of a substance results in the decrease in its density by increasing its volume.
Relative density, as the name suggests, is described as the ratio of the density of a material to the density of a given reference material. It is also called the specific gravity.
Specific gravity for liquids is nearly always measured with respect to water at its densest and for gases; the reference is air at the room temperature. If the relative density of a material is less than one then it is less dense than the reference material; if greater than one then it is denser than the reference material. If the value of relative density is exactly one, then the density of both the materials is equal; that is, equal volumes of the two materials have the same mass.
In case the reference material is water, then a substance with a relative density less than one will float on the surface of water. A substance having relative density greater than one will sink.

Note:
Density of an object is a measure of its mass per unit volume. The average or absolute density of an object equals total mass of the object divided by its total volume. For a fixed amount of mass, density is inversely proportional to the volume; that is, a material or an object derived from a relatively dense material would have less volume as compared to an object of equal mass made from some less dense material. In order to simplify the comparisons of density across different systems of units, it is replaced by the dimensionless quantity relative density or specific gravity, which is essentially the ratio of the density of the material to the density of the standard material.