## Question

A piece of copper having an internal cavity weights 264 g in air and 221 g in water. The density of copper is 8.8 gm^{–3}. What is the volume of the cavity?

### Solution

13 cm^{3}

Apparent loss of mass of copper = 264 – 221 = 43 g. This is the mass of water displaced by copper piece when it is immersed in water. Volume of copper piece with cavity = 43 cm^{3}. Volume of copper only is .

Therefore, the volume of the cavity = 43 – 30 = 13 cm^{3}.

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