Question

A U-tube is partially filled with water. Oil which does not mix with water is next poured into one side, until water rises by 25 cm on the other side. If the density of oil `0.8g//cm^(3)`. The oil level will stand higher than the water by
A. `6.25cm`
B. `12.50cm`
C. `31.75cm`
D. `62.50cm`

Answer 1

Correct Answer - B
On pouring oil on the left side water sides by `25 cm` from its previous level in the right limb of `U`-tube, creating a difference of levels of water by `50 cm`. Let `h cm` be the height of oil above level `A` in the left limb of `U`-tube. Equating pressures at `A` and `B` we get `P_(A)=P_(B)`
`implieshxxrho_("oil")xxg=50rho_("water")xxg`
`impliesh=(50xxrho_("water"))/rho_("oil")=(50xx1)/0.8=62.5cm`
Difference of level of oil `C` and water `D` in the two limbs
`=62.5-50=12.5cm`