Question

A piece of solid weighs 120 g in air, 80 g in water and 60 g in a liquid. The relative density of the solid and that of the liquid are respectively.

• A. 3, 1.5
• B. 2, 3/4
• C. 3/2, 2
• D. 4, 3

Answer 1

The correct option is A 3, 1.5

The relative density of an object is equal to the ratio of its weight in air and the difference of its weight in air and its weight when the object is submerged in water.

$D=\frac{wa}{wa-ww}$

From the given data $D=\frac{120}{120-80}$

$D=\frac{120}{b40}$

$D=3.$

The relative density of oil can be calculated as,

Relative density of oil $=\frac{Lossinweighinoil}{Lossinweighinwater}$

Relative density of oil $=\frac{120–60}{120-80}$

Relative density of oil $=\frac{60}{40}$

Relative density of oil $=1.5$