NEET Physics - New - Mechanical Properties of Fluids

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Question - 1

A capillary tube of radius r is immersed in water and water rises in it to a height h. The mass of the water in the capillary is 5 g. Another capillary tube of radius 2 r is immersed in water. The mass of water that will rise in this tube is_____

  • A \(20.0 \mathrm{~g}\)
  • B \(2.5 \mathrm{~g}\)
  • C \(5.0 \mathrm{~g}\)
  • D \(10.0 \mathrm{~g}\)

Question - 2

A small hole of area of cross-section \(2 \mathrm{~mm}^{2}\) is present near the bottom of a fully filled open tank of height 2 m. Taking \(g=10 \mathrm{~m} / \mathrm{s}^{2}\), the rate of flow of water through the open hole would be nearly____

  • A \(8.9 \times 10^{-6} \mathrm{~m}^{3} / \mathrm{s}\)
  • B \(2.23 \times 10^{-6} \mathrm{~m}^{3} / \mathrm{s}\)
  • C \(6.4 \times 10^{-6} \mathrm{~m}^{3} / \mathrm{s}\)
  • D \(12.6 \times 10^{-6} \mathrm{~m}^{3} / \mathrm{s}\)

Question - 3

A soap bubble, having radius of 1 mm, is blown from a detergent solution having a surface tension of \(2.5 \times 10^{-2}\) \(\mathrm{N} / \mathrm{m}\). The pressure inside the bubble equals at a point Z below the free surface of water in a container. Taking \(\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^{2}\), density of water \(=10^{3} \mathrm{~kg} / \mathrm{m}^{3}\), the value of \(Z_{0}\) is____

  • A 10 cm
  • B 1 cm
  • C 0.5 cm
  • D 100 cm

Question - 4

Three liquids of densitites \(\mathrm{r}_{1}, \mathrm{r}_{2}\) and \(\mathrm{r}_{3}\) (with \(\mathrm{r}_{1}>\mathrm{r}_{2}>\mathrm{r}_{3}\) ), having the same value of surface tension T, rise to the same height in three identical capillaries. The angle of contact \(\mathrm{q}_{1}, \mathrm{q}_{2}\) and \(\mathrm{q}_{3}\) obey____

  • A \(\frac{\pi}{2}>\theta_{1}>\theta_{2}>\theta_{3} \geq 0\)
  • B \(0 \leq \theta_{1}>\theta_{2}>\theta_{3}<\frac{\pi}{2}\)
  • C \(\frac{\pi}{2}<\theta_{1}>\theta_{2}>\theta_{3} \geq \pi\)
  • D \(\pi>\theta_{1}>\theta_{2}>\theta_{3} \geq \frac{\pi}{2}\)

Question - 5

A wind with speed \(40 \mathrm{~m} / \mathrm{s}\) blows parallel to the roof of a house. The area of the roof is \(250 \mathrm{~m}^{2}\). Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be \(\left(\mathrm{P}_{\text {air }}=1.2 \mathrm{~kg} / \mathrm{m}^{3}\right)\)____

  • A 4.8×105 N,upwards
  • B 2.4×105 N,upwards
  • C 2.4×105 N,downwards
  • D 4.8×105 N,downwards

Question - 6

A certain number of spherical drops of a liquid of radius 'r ' coalesce to form a single drop of radius ' R' and volume ' V . If ' T ' is the surface tension of the liquid, then

  • A energy \(=4 V T\left(\frac{1}{r}-\frac{1}{R}\right)\) is released
  • B energy \(=3 V T\left(\frac{1}{r}+\frac{1}{R}\right)\) is absorbed
  • C energy \(=3 V T\left(\frac{1}{r}-\frac{1}{R}\right)\) is released
  • D energy is nèither released nor absorbed

Question - 7

A fluid is in streamline flow across a horizontal pipe of variable area of cross section. For this which of the following statements is correct?

  • A The velocity is maximum at the narrowest part of the pipe and the pressure is maximum at the widest part of the pipe
  • B Velocity and pressure both are maximum at the narrowest part of the pipe
  • C Velocity and pressure both are maximum at the widest part of the pipe
  • D The velocity is minimum at the narrowest part of the pipe and pressure is minimum at the widest part of the pipe

Question - 8

The wetability of a surface by a liquid depends primarily on

  • A viscosity
  • B surface tension
  • C density
  • D angle of contact between the surface and the liquid

Question - 9

A rectangular block of mass m and area of cross section A floats in a liquid of density r. If it is given a small vertical displacement from equilibrium it undergoes oscillation. with a time period T. Then_____

  • A \(T \alpha \frac{1}{\sqrt{A}}\)
  • B \(T \times \frac{1}{\rho}\)
  • C \(T, \alpha \frac{1}{\sqrt{m}}\)
  • D \(T \alpha \sqrt{\mathrm{p}}\)

Question - 10

The angle ofcontact between pure water and pure glass is_____

  • A 0o
  • B 45o
  • C 90o
  • D 135o