A steel block having an internal cavity weighs 234g in air and 197g in water. If the density of steel is `7.8 g cm^(-3)` then the volume of the cavity is

Options

A. `5cm^(3)`
B. `7 cm^(3)`
C. `9 cm^(3)`
D. `11 cm^(3)`

Answer

B

Explanation

Weight of water displaced by steel block
= Loss of weight of block in water
`=(234-197)gf = 37gf`
Volume of water displaced = `37 cm^(3)`
This is the volume of the block with cavity.
Volume of cavity = (37-30)cm^(3) = 7 cm^(3)`.