Question

A body of mass 'm' expands and its volume increases to two times its original volume. The density of the body .

• A. remains constant
• B. is reduced by half
• C. becomes twice

Answer 1

The correct option is B is reduced by half

Let the initial mass and volume be '$m$' and '$v$' respectively and the density be $d_1$. From definition of density,
$d_1=\frac{m}{v}$
When the volume is doubled, the density $d_2$ becomes:
$d_2=\frac{m}{2v}$
$d_2=\frac{1}{2}\times \frac{m}{v}$
$d_2=\frac{1}{2}\times d_1$
$\therefore$ the density becomes half of the original.