Question

A golden crown weigh 386 g in air. If the density of gold is $19.3gc{m}^{-3}$ , what will be its weight in water?

• A. 406 g
• B. 366 g
• C. 300 g
• D. 400 g

Answer 1

The correct option is B 366 g

Weight of crown in air = 386 g
Density = $19.3gc{m}^{-3}$
Volume of the crown = $\frac{386}{19.3}$$\frac{}{}=20c{m}^3$

Therefore, according to Archimedes principle, when the crown is dipped in water, water of volume equal to the volume of the crown i.e. 20 $c{m}^3$ will be displaced. The loss in the weight of the crown will be equal to the weight of displaced water.

Weight of displaced water = $20c{m}^3\times 1gc{m}^{-3}\left(densityofwater\right)=20g$Weight of the crown in water
= weight in air - loss in weight
= 386 -20 = 366 g
Thus, weight of the crown in water is 366 g.