Question

A $U$ tube is partially filled with water oil which does not mix with water is next poured in to one side until water rises by $25\,cm$ on the other side. If the relative density of oil be $0.8$ the oil level will stand higher than the water level by :-

• A. $6.25\,cm$
• B. $12.50\,cm$
• C. $31.25\,cm$
• D. $20\,cm$

Answer 1

Answer: (B)

$h_{1}\rho _{1}=h_{2}\rho _{2}$
$h_{1}\times 0.8\left(2 \times 25\right)\times 1$
$h_{1}=\frac{50}{0 . 8}=62.5\,cm$
Level difference $=h_{1}-h_{2}=62.5-50=12.5\,cm$