Question

The density of glycerine is $1260kg{m^{ - 3}}$. What is the relative density? (Density of water is $1000kg{m^{ - 3}}$)
A. 0.63
B. 1.26
C. 12.6
D. 6.3

Answer 1

Hint:Here,we are going to use the concept of density.It is the ratio of mass of the object to volume of the object. And its SI unit is $kg/{m^3}$. Relative density is the ratio of density of the object to the density of water at ${4^ \circ }C$.

Complete step by step answer:
We are given that the density of glycerine is $1260kg{m^{ - 3}}$
We have to find its relative density.
Relative density of a body is the ratio of density of the body to density of the water.
$R{D_{body}} = \dfrac{{Densit{y_{body}}}}{{Densit{y_{water}}}}$
Density of glycerine is $1260kg{m^{ - 3}}$ and density of water is $1000kg{m^{ - 3}}$
$
R{D_{glycerine}} = \dfrac{{{D_{glycerine}}}}{{{D_{water}}}} \\
{D_{glycerine}} = 1260kg{m^{ - 3}},{D_{water}} = 1000kg{m^{ - 3}} \\
R{D_{glycerine}} = \dfrac{{1260}}{{1000}} \\
R{D_{glycerine}} = 1.26 \\
$
The relative density of Glycerine is 1.26.
The correct option is Option B, 1.26.

Additional Information:
Relative density is an important physical quantity that gives information about the nature of the object. For example the relative density of glycerine is 1.26. It means that the glycerine is 1.26 times greater than that of water. So we can say that the glycerine sinks water. Similarly if the relative density of wood is 0.6, it means that its density is less than that of water. Hence wood floats on water.So we can say that if relative density is less than 1 then those objects float on water and if relative density is more than 1 then those objects sink in water.

Note:Relative density is also known as specific gravity. Do not confuse density with relative density as density is the mass per unit volume and relative density is the density of a body with respect to the density of another body. Relative density is the ratio of the same physical quantities so it does not have any units.