Question

Find out the SI unit of density?
$\begin{align}
  & A.gc{{m}^{-3}} \\
 & B.g{{m}^{-3}} \\
 & C.kg{{m}^{-3}} \\
 & D.kgc{{m}^{-3}} \\
\end{align}$

Answer 1

Hint: The density of a body is defined as the mass per unit volume of the body. The density is found by taking the ratio of the mass of the body to the volume of the body. Take the SI unit of mass as well as volume and divide it. This will help you in answering this question.

Complete answer:
As we all know the SI unit if mass has been given as,
$m=kg$
In the same way the SI unit of the volume can be written as,
$V={{m}^{3}}$
The density of the body is found by taking the ratio of the mass of the body to the volume of the body. That is we can write that,
$D=\dfrac{M}{V}$
Where $M$ be the mass of the body and $V$ be the volume of the body.
Let us substitute these units in the equation in order to calculate the unit for the density of the body. That is we can write that,
$\text{unit of }D=\dfrac{kg}{{{m}^{3}}}$
Hence the unit of density has been obtained.

It is mentioned as the option C.

Note:
The density can also be known as volumetric mass density or the specific mass. The density of a substance can be defined as the mass per unit volume. The symbol we use for the density is $\rho $ although the Latin letter $D$ can also be used for symbolising. In the case of a pure substance the density is having the same numerical value as that of its mass concentration. Each and every material is generally having different densities. This density will be relevant to the case of buoyancy, purity and also packaging. The densest known elements at standard conditions for temperature and pressure are found to be Osmium and Iridium.