Exams › NEET › Physics

A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of 10 mm above the water level on the other side. Meanwhile the water rises by 65 mm from its original level (see diagram). The density of the oil is:

1. 425 kg/m³
2. 800 kg/m³
3. 928 kg/m³
4. 650 kg/m³

Correct answer: 650 kg/m³

Solution

The pressure at the same horizontal level in both arms of the U-tube must be equal. Using the hydrostatic pressure formula, equate the pressure due to the column of oil to the pressure due to the column of water. Solving gives the density of oil as 650 kg/m³.

Related NEET Physics questions

• If the air density were uniform, then the height of the atmosphere above the sea level to produce a normal atmospheric pressure of \( 1.0 \times 10^{5} \) Pa is (density of air is \( 1.3 \mathrm{kg} / \mathrm{m}^{3}, \mathrm{g}=10 \mathrm{m} / \mathrm{s}^{2} \) ):
• 1atm \( = \)
• The atmospheric pressure at is 100,000 pascal.
• According to Newton, the viscous force acting between liquid layers of area A and velocity gradient ΔV/ΔZ is given by \( F = -ηA \frac{ΔV}{ΔZ} \) where η is constant called coefficient of viscosity. The dimensional formula of η is
• As we know that, surface tension(s) is:
• The cylindrical tube of a spray pump has radius, R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is V, the speed of the ejection of the liquid through the holes is:

⚔️ Practice NEET Physics free + battle 1v1 →