Question

The mass and volume of a body are $4.237 \,g$ and $2.5 \,cm^3$, respectively. The density of the material of the body in correct significant figures is

• A. $1.6948\, g\,cm^{-3}$
• B. $1.69\, g\,cm^{-3}$
• C. $1.7\, g\,cm^{-3}$
• D. $1.695\, g\,cm^{-3}$

Answer 1

Answer: (C)

Here, mass, $m = 4.237 \,g$
Volume, $V = 2.5 \,cm^3$
Density, $\rho=\frac{\text{Mass}}{\text{Volume}}=\frac{4.237\,g}{2.5\,cm^{3}}$
$=1.6948\,g\,cm^{-3}$
As mass has $4$ significant figures and volume has $2$ significant figures, therefore, as per rule, density will have only two significant figures. Rounding off to two significant figures, we get, $\rho=1.7\,g\,cm^{-3}$