When a cube of wood floats in water,`60%` of its volume is submerged. When the same cube floats in an unknown fluid `85%` of its volume is submerged. Find the densities of wood and the unknown fluid.

Answer

C

Explanation

Fraction of volume immersed is given by
`f=(rho_s)/(rho_l)`
In first case `0.6=(rho_s)/(rho_w)=(rho_s)/(1)`
or, `rho_(s)=0.6 g//cm^(3)`=density of wood
In second case
`0.8=(rho_s)/(rho_l)=(0.6)/(rho_e)`
or, `rho_(l)=(0.6)/(0.85)`
`=0.705 g//cm^(3)`.