Question

If a piece of copper having internal cavity weighs 264 gms. in air and 221 gms. in water, then volume of the cavity is ........................ . (Density of copper $=$ 8.8 g/cm${}^3$)

• A. $10c{m}^3$
• B. $11c{m}^3$
• C. $13c{m}^3$
• D. $15c{m}^3$

Answer 1

The correct option is C $13c{m}^3$

If a piece of copper having internal cavity weight $264$ gms in air and $221$ gms in water, then volume of the cavity is

density of copper $=8.8$ $g/{cm}^3$.

Using the principle of $Ap$ ehimedus law,

Volume of case of air $\left(V_1\right):\frac{264}{8.8}=30gm/{cm}^3$

$\therefore$ Volume in case of water $V_2=\frac{264-221}{1}=43gm$

Now, volume in the cavity $=V_2-V_1=43-30=13{cm}^3$