Question

A vertical U-tube of uniform inner cross section contains mercury in both sides of its arms. A glycerin (density =1.3 $\frac{g}{c{m}^3}$ column of length 10 cm is introduced into one of its arms. Oil of density 0.8 $\frac{g}{c{m}^3}$ is poured into the other arm until the upper surfaces of the oil and glycerin are in the same horizontal level. Find the length of the oil column, Density of mercury =
$13.6\frac{g}{c{m}^3}$

• A. 10.4 cm
• B. 8.2 cm
• C. 7.2 cm
• D. 9.6 cm

Answer 1

The correct option is D 9.6 cm


At the condition of equilibrium
Pressure at point A = Pressure at point B
$P_A=P_B\Rightarrow 10\times 1.3\times g=h\times 0.8\times g+(10-h)\times 13.6\times g$
After solving we get

h = 9.6 cm

Hence the level of the oil column is 9.6 cm