Question

Unit of density and relative density are the same.

A. True

B. False

Answer 1

Hint: Try to understand the definition of density and relative density. Then try to determine their units. Then compare them to see if the question is true or false.

Complete step by step answer:

Density of an object can be defined as the mass per unit volume. The symbol mostly used for density is $\rho $.

Density of an object can be expressed as,

$\rho =\dfrac{m}{V}$

Where $\rho $ is the density, m is the mass of the object and V is the volume of the object.

Considering SI units, the unit of mass is Kg and the unit of volume is ${{m}^{3}}$.

So, the unit of density will be $Kg{{m}^{-3}}$.

Relative density of an object can be defined as the ratio of the density of an object to the density of a reference material. The reference material used for measuring relative density is usually water for solid or liquid, and air for gas.

Since relative density is just a ratio of the density of the two materials, relative density will be unitless.

So, density has a SI unit of $Kg{{m}^{-3}}$ and the relative density is unitless. So, the units of the two quantities are not the same.

Therefore, it is not true that Units of density and relative density are the same. The given statement is false. So, option (B) is correct.

Note: Relative quantity is a measure of a physical quantity with respect to a standard quantity or any other quantity given in question. The absolute measurement is irrespective of other objects. Density is an absolute quantity and the relative density is a relative quantity.