Question

A beaker of 2 litre is fully filled with a liquid. The value of the relative density of the liquid is $0.7$. Find out the value of mass of the liquid.
(Density of water$=1gc{m}^{-3}$ )

• A. $2.7kg$
• B. $0.7kg$
• C. $1.4kg$
• D. $2kg$

Answer 1

The correct option is C $1.4kg$

Given:
Volume of liquid,
$V$ $=2l=0.002m^3$
Relative density (${\rho }_r$) $=0.7$
Density of water$\left({\rho }_w\right)=1gc{m}^{-3}$
Let's assume that the density of liquid is $\rho$ and mass of liquid is $M$
We know that, relative density,
${\rho }_r=\frac{\rho }{{\rho }_w}$

$0.7=\frac{\rho }{1}$
$⟹\rho =0.7gc{m}^{-3}=700kg{m}^{-3}$

We know that density of liquid,
$\rho =\frac{M}{V}$
$700=\frac{M}{0.002}$
$M=700\times 0.002=1.4kg$
Hence, mass of the liquid is $1.4kg$