Question

A block of wood floats in freshwater with two-third of its volume submerged. In oil, the block floats with one-fourth of its volume submerged. The density of oil is

• A. $2666.7 \, kgm^{- 3}$
• B. $5333.3 \, kgm^{- 3}$
• C. $1333.3 \, kgm^{- 3}$
• D. $3333.3 \, kgm^{- 3}$

Answer 1

Answer: (A)

$\rho _{w} \, \frac{2}{3} \, V=\rho _{b}V$
$\rho _{o i l} \, \frac{1}{4} \, V=\rho _{b}V$
$\therefore \, \frac{2}{3} \, \rho _{w}=\frac{1}{4} \, \rho _{o i l}$
$\rho _{o i l}=\frac{8}{3} \, \rho _{w}$
$=\frac{8000}{3}=2666.7$