Question

Following observations are taken while finding the relative density of cork. Find the relative density of the cork.

(I) Weight of sinker in water = 12.6 g
(II) Weight of sinker in water + cork in air = 13.7 g
(III) Weight of sinker and cork, both in water = 10.5 g

• A. 1.2
• B. 0.9
• C. 0.6
• D. 0.3

Answer 1

The correct option is D

0.3

Weight of cork in air = 13.7 - 12.6 = 1.1 g
Weight of cork in water = 10.5 - 12.6 = -2.1 g
Since, cork floats in water, up thrust on it is more than its own weight as it is made to sink with the force of the sinker, hence weight of the cork in water is negative.
Relative density of cork $=\frac{\text{weight in air}}{\text{loss of weight in water}}=\frac{1.1}{1.1-(-2.1)}=0.33$