NEET Mechanical Properties of Fluids PYQ practice sheet

9 previous-year NEET Physics questions from Mechanical Properties of Fluids, newest papers first. Mechanical Properties of Fluids carries 11 of the Physics questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

1. 1.

   RE-NEET 2026

   Water flows in a streamline motion through a horizontal pipe of circular cross-section as shown in the figure. The pressure difference of water between $P$ and $Q$ is $15\ \mathrm{Nm^{-2}}$. The area of cross-section at $P$ and $Q$ are $40\ \mathrm{cm^2}$ and $20\ \mathrm{cm^2}$, respectively. The rate of flow of water through the pipe, in $\mathrm{cm^3s^{-1}}$, is: [Take density of water $= 1000\ \mathrm{kg\,m^{-3}}$] Figure: a horizontal pipe that is wide at $P$ and narrows at $Q$.

   • (A)
     $300$
   • (B)
     $100$
   • (C)
     $400$
   • (D)
     $200$
2. 2.

   RE-NEET 2026

   In the measurement of viscosity of liquids using terminal velocity experiment, spherical balls of same radius but having different densities are used. The variation of the terminal velocity ($v$) with the ratio of density of spherical ball ($\sigma$) to density of the liquid ($\rho$), is best represented by: Each option is a graph of $v$ (vertical axis) against $\sigma/\rho$ (horizontal axis) with a vertical line drawn at $\sigma/\rho = 1$.

   • (A)
     
   • (B)
     
   • (C)
     
   • (D)
     
3. 3.

   NEET 2026

   A submarine is designed to withstand an absolute pressure of 100 atm. How deep can it go below the water surface? (Consider the density of water $=1000\ \text{kg m}^{-3}$, $1\ \text{atm}=1\times10^{5}$ Pa and gravitational acceleration $g=10\ \text{m s}^{-2}$)

   • (A)
     9900 m
   • (B)
     9000 m
   • (C)
     990 m
   • (D)
     99 m
4. 4.

   NEET 2024

   A thin flat circular disc of radius 4.5 cm is placed gently over the surface of water. If surface tension of water is $0.07\ \text{N m}^{-1}$, then the excess force required to take it away from the surface is:

   • (A)
     19.8 mN
   • (B)
     198 N
   • (C)
     99 N
   • (D)
     1.98 mN
5. 5.

   NEET 2023

   The amount of energy required to form a soap bubble of radius $2\ \mathrm{cm}$ from a soap solution is nearly : (surface tension of soap solution $= 0.03\ \mathrm{N\,m^{-1}}$)

   • (A)
     $50.1\times10^{-4}\ \mathrm{J}$
   • (B)
     $30.16\times10^{-4}\ \mathrm{J}$
   • (C)
     $5.06\times10^{-4}\ \mathrm{J}$
   • (D)
     $3.01\times10^{-4}\ \mathrm{J}$
6. 6.

   NEET 2022

   If a soap bubble expands, the pressure inside the bubble:

   • (A)
     is equal to the atmospheric pressure
   • (B)
     decreases
   • (C)
     increases
   • (D)
     remains the same
7. 7.

   NEET 2022

   A spherical ball is dropped in a long column of a highly viscous liquid. The curve in the graph shown, which represents the speed of the ball ($v$) as a function of time ($t$), is: (Figure: $v$ on the vertical axis and $t$ on the horizontal axis, with four labelled curves A, B, C, D starting from the origin; curve B rises and then flattens out to a constant value as $t$ increases, consistent with the ball reaching terminal velocity.)

   • (A)
     D
   • (B)
     A
   • (C)
     B
   • (D)
     C
8. 8.

   NEET 2021

   The velocity of a small ball of mass $M$ and density $d$, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is $\dfrac{d}{2}$, then the viscous force acting on the ball will be :

   • (A)
     $2Mg$
   • (B)
     $\dfrac{3}{2}Mg$
   • (C)
     $Mg$
   • (D)
     $\dfrac{Mg}{2}$
9. 9.

   NEET 2020

   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 $2r$ is immersed in water. The mass of water that will rise in this tube is :

   • (A)
     2.5 g
   • (B)
     5.0 g
   • (C)
     10.0 g
   • (D)
     20.0 g