Question

The mass and volume of a body are 4.237 g and 2.5 cm³, 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)

1.7 g cm^-3

Answer 2

Here, mass, $\mathrm { m } = 4.237 \mathrm {~g}$

Volume, $\mathrm { V } = 2.5 \mathrm {~cm} ^ { 3 }$ Density,

$\rho = \frac { \text { Mass } } { \text { Volume } } = \frac { 4.237 \mathrm {~g} } { 2.5 \mathrm {~cm} ^ { 3 } } = 1.6948 \mathrm {~g} \mathrm {~cm} ^ { - 3 }$ 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 $\rho = 1.7 \mathrm {~g} \mathrm {~cm} ^ { - 3 }$