Question

A block of wood is floating on oil with half of its volume submerged. If the density of oil $840kg{m}^{-3}$, the relative density of wood (relative to water) is

• A. 0.84
• B. 0.42
• C. 0.21
• D. 1

Answer 1

The correct option is B 0.42

$\frac{v}{V}=\frac{d_w}{d_L}$
$\frac{1}{2}=\frac{d_w}{840}\Rightarrow d_w=420kg/m^{-3}$
$R.D.=\frac{420}{{10}^3}=0.42$