JEE-MAIN SERIES

Physics

Mechanical Properties Of Fluid

40 previous year questions.

Volume: 40 Ques

Yield: High

High-Yield Trend

2

2026

9

2023

7

2022

2

2021

4

2020

7

2019

1

2018

1

2016

4

2014

3

2013

Chapter Questions
40 MCQs

01

PYQ 2013

medium

physics ID: jee-main

In an experiment, a small steel ball falls through a liquid at a constant speed of . If the steel ball is pulled upward with a force equal to twice its effective weight, how fast will it move upward ?

1

5 cm/s

2

Zero

3

10 cm/s

4

20 cm/s

02

PYQ 2013

easy

physics ID: jee-main

Air of density is blowing across the horizontal wings of an aeroplane in such a way that its speeds above and below the wings are and, respectively. The pressure difference between the upper and lower sides of the wings, is :

1

2

3

4

03

PYQ 2013

medium

physics ID: jee-main

Assume that a drop of liquid evaporates by decrease in its surface energy, so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is, density of liquid is and is its latent heat of vaporization.

1

2

3

4

04

PYQ 2014

medium

physics ID: jee-main

An open glass tube is immersed in mercury in such a way that a length of 8 cm extends above the mercury level. The open end of the tube is then closed and sealed and the tube is raised vertically up by additional 46 cm What will be length of the air column above mercury in the tube now ? (Atmospheric pressure = of Hg)

1

16 cm

2

22 cm

3

38 cm

4

6 cm

05

PYQ 2014

medium

physics ID: jee-main

An air bubble of radius is in a liquid having surface tension and density . The pressure inside the bubble is 1100 greater than the atmospheric pressure. At what depth is the bubble below the surface of the liquid ?

1

0.1 m

2

0.15 m

3

0.20 m

4

0.25 m

06

PYQ 2014

medium

physics ID: jee-main

A capillary tube is immersed vertically in water and the height of the water column is . When this arrangement is taken into a mine of depth, the height of the water column is . If is the radius of earth, the ratio is :

1

2

3

4

07

PYQ 2014

medium

physics ID: jee-main

The average mass of rain drops is kg and their average terminal velocity is Calculate the energy transferred by rain to each square metre of the surface at a place which receives of rain in a year.

1

2

3

4

08

PYQ 2016

medium

physics ID: jee-main

Consider a water jar of radius that has water filled up to height and is kept on a stand of height (see figure). Through a hole of radius at its bottom, the water leaks out and the stream of water coming down towards the ground has a shape like a funnel as shown in the figure. If the radius of the cross-section of water stream when it hits the ground is . Then :

1

2

3

4

09

PYQ 2018

medium

physics ID: jee-main

When an air bubble of radius rises from the bottom to the surface of a lake, its radius becomes . Taking the atmospheric pressure to be equal to eight of water column, the depth of the lake would approximately be (ignore the surface tension and the effect of temperature) :

1

11.2 m

2

8.7 m

3

9.5 m

4

10.5 m

10

PYQ 2019

medium

physics ID: jee-main

A wooden block floating in a bucket of water has of its volume submerged. When certain amount of an oil is poured into the bucket, it is found that the block is just under the oil surface with half of its volume under water and half in oil. The density of oil relative to that of water is :

1

0.5

2

0.7

3

0.6

4

0.8

11

PYQ 2019

medium

physics ID: jee-main

If is the mass of water that rises in a capillary tube of radius, then mass of water which will rise in a capillary tube of radius is :

1

2

3

4

12

PYQ 2019

medium

physics ID: jee-main

The top of a water tank is open to air and its water level is maintained. It is giving out water per minute through a circular opening of radius in its wall. The depth of the centre of the opening from the level of water in the tank is close to :

1

9.6 m

2

4.8 m

3

2.9 m

4

6.0 m

13

PYQ 2019

medium

physics ID: jee-main

A load of mass is suspended from a steel wire of length and radius in Searle's apparatus experiment. The increase in length produced in the wire is . Now the load is fully immersed in a liquid of relative density . The relative density of the material of load is . The new value of increase in length of the steel wire is :

1

4.0 mm

2

3.0 mm

3

5.0 mm

4

zero

14

PYQ 2019

medium

physics ID: jee-main

Water flows into a large tank with flat bottom at the rate of . Water is also leaking out of a hole of area at its bottom. If the height of the water in the tank remains steady, then this height is :

1

4 cm

2

2.9 cm

3

1.7 cm

4

5.1 cm

15

PYQ 2019

medium

physics ID: jee-main

Water from a tap emerges vertically downwards with an initial speed of . The crosssectional area of the tap is . Assume that the pressure is constant throughout the stream of water and that the flow is streamlined. The cross-sectional area of the stream, below the tap would be : (Take)

1

2

3

4

16

PYQ 2019

medium

physics ID: jee-main

A soap bubble, blown by a mechanical pump at the mough of a tube, increases in volume, with time, at a constant rate. The graph that correctly depicts the time dependence of pressure inside the bubble is given by :

1

2

3

4

17

PYQ 2020

medium

physics ID: jee-main

Water flows in a horizontal tube (see figure). The pressure of water changes by between and where the area of cross section are and, respectively. Find the rate of flow of water through the tube. (density of water =)

1

2

3

4

18

PYQ 2020

medium

physics ID: jee-main

An ideal fluid flows (laminar flow) through a pipe of non-uniform diameter. The maximum and minimum diameters of the pipes are and, respectively. The ratio of the minimum and the maximum velocities of fluid in this pipe is :

1

2

3

4

19

PYQ 2020

easy

physics ID: jee-main

A small spherical droplet of density is floating exactly half immersed in a liquid of density and surface tension . The radius of the droplet is (take note that the surface tension applies an upward force on the droplet):

1

2

3

4

20

PYQ 2020

medium

physics ID: jee-main

In an experiment to verify Stokes law, a small spherical ball of radius and density falls under gravity through a distance in air before entering a tank of water. If the terminal velocity of the ball inside water is same as its velocity just before entering the water surface, then the value of is proportional to (ignore viscosity of air)

1

2

3

4

21

PYQ 2021

easy

physics ID: jee-main

Two narrow bores of diameter 5.0 mm and 8.0 mm are joined together to form a U-shaped tube open at both ends. If this U-tube contains water, what is the difference in the level of two limbs of the tube. [Take surface tension of water, angle of contact, and density of water kg]

1

5.34 mm

2

3.62 mm

3

4.97 mm

4

2.19 mm

22

PYQ 2021

medium

physics ID: jee-main

A hydraulic press can lift 100 kg when a mass 'm' is placed on the smaller piston. It can lift _________ kg when the diameter of the larger piston is increased by 4 times and that of the smaller piston is decreased by 4 times keeping the same mass 'm' on the smaller piston.

23

PYQ 2022

medium

physics ID: jee-main

The terminal velocity of the spherical rain drop depends on the radius (r) of the spherical rain drop as

1

2

3

4

24

PYQ 2022

medium

physics ID: jee-main

A water drop of radius 1 μm falls in a situation where the effect of buoyant force is negligible. Co-efficient of viscosity of air is and its density is negligible as compared to that of water . Terminal velocity of the water drop is

1

2

3

4

25

PYQ 2022

medium

physics ID: jee-main

The bulk modulus of a liquid is 3 \times 10 10 Nm -2 . The pressure required to reduce the volume of liquid by 2% is

1

3 \times 108 Nm–2

2

9 \times 108 Nm–2

3

6 \times 108 Nm–2

4

12 \times 108 Nm–2

26

PYQ 2022

easy

physics ID: jee-main

If momentum [P], area [A] and time [T] are taken as fundamental quantities, then the dimensional formula for the coefficient of viscosity is

1

[PA -1 T 0]

2

[PAT -1]

3

[PA -1 T]

4

[PA -1 T -1]

27

PYQ 2022

medium

physics ID: jee-main

Consider a cylindrical tank of radius is filled with water. The top surface of water is at from the bottom of the cylinder. There is a hole on the wall of cylinder at a height of from the bottom. A force of is applied on the top surface of water using a piston. The speed of efflux from the hole will be: (Given atmosphere pressure, density of water and gravitational acceleration)

1

11.6 m/s

2

10.8 m/s

3

17.8 m/s

4

14.4 m/s

28

PYQ 2022

medium

physics ID: jee-main

A small spherical ball of radius 0.1 mm and density 104 kg m–3 falls freely under gravity through a distance h before entering a tank of water. If, after entering the water the velocity of ball does not change and it continue to fall with same constant velocity inside water, then the value of h will be ______ m.(Given g = 10 ms–2, viscosity of water = 1.0 \times 10–5 N-sm–2).

29

PYQ 2022

medium

physics ID: jee-main

The area of cross-section of a large tank is . It has a narrow opening near the bottom having area of cross-section . A load of is applied on the water at the top in the tank. Neglecting the speed of water in the tank, the velocity of the water, coming out of the opening at the time when the height of water level in the tank is above the bottom, will be ______. [Take]

30

PYQ 2023

hard

physics ID: jee-main

If 1000 droplets of water of surface tension 0.07 N/ m, having same radius 1 mm each, combine to from a single drop In the process the released surface energy is - (Take π=)

1

2

3

4

31

PYQ 2023

medium

physics ID: jee-main

A spherical ball of radius and density is dropped in glycerine of coefficient of viscosity and density . The viscous force on the ball when it attains constant velocity is . The value of is: (Given, and)

32

PYQ 2023

medium

physics ID: jee-main

The surface of water in a water tank of cross section area on the top of a house is above the tap level. The speed of water coming out through the tap of cross section area is . At that instant, is . The value of will be _________.

33

PYQ 2023

medium

physics ID: jee-main

A sphere of density ρ & mass m is moving down with constant velocity in viscous liquid of density ρ 0 . Find out viscous force on sphere

1

2

3

4

34

PYQ 2023

medium

physics ID: jee-main

A small ball of mass M and density is dropped in a viscous liquid of density . After some time, the ball falls with a constant velocity. What is the viscous force on the ball ?

1

2

3

4

35

PYQ 2023

hard

physics ID: jee-main

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : A spherical body of radius (5 \pm 0.1) mm having a particular density is falling through a liquid of constant density. The percentage error in the calculation of its terminal velocity is 4%. Reason R : The terminal velocity of the spherical body falling through the liquid is inversely proportional to its radius.

1

Both A and R are true and R is the correct explanation of A

2

Both A and R are true but R is NOT the correct explanation of A

3

A is true but R is false

4

A is false but R is true

36

PYQ 2023

medium

physics ID: jee-main

Eight equal drops of water are falling through air with a steady speed of 10 cm/s. If the drops coalesce, the new velocity is :

1

5 cm/s

2

40 cm/s

3

16 cm/s

4

10 cm/s

37

PYQ 2023

hard

physics ID: jee-main

A fully loaded boeing aircraft has a mass of kg. Its total wing area is . It is in level flight with a speed of 1080 km/h. If the density of air 𝜌 is , the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface in percentage will be. ( )

1

16

2

10

3

8

4

6

38

PYQ 2023

medium

physics ID: jee-main

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: When you squeeze one end of a tube to get toothpaste out from the other end, Pascal's principle is observed. Reason R: A change in the pressure applied to an enclosed incompressible fluid is transmitted undiminished to every portion of the fluid and to the walls of its container. In the light of the above statements, choose the most appropriate answer from the options given below:

1

Both A and R are correct and R is the correct explanation of A

2

Both A and R are correct but R is NOT the correct explanation of A

3

A is not correct but R is correct

4

A is correct but R is not correct

39

PYQ 2026

medium

physics ID: jee-main

Water flows through a horizontal tube as shown in the figure. The difference in height between the water columns in vertical tubes is 5 cm and the area of cross-sections at A and B are 6 cm and 3 cm respectively. The rate of flow will be ______ cm /s. (take g = 10 m/s).

1

2

3

4

40

PYQ 2026

hard

physics ID: jee-main

Given below are two statements: Statement I: Pressure of a fluid is exerted only on a solid surface in contact as the fluid-pressure does not exist everywhere in a still fluid. Statement II: Excess potential energy of the molecules on the surface of a liquid, when compared to interior, results in surface tension. In the light of the above statements, choose the correct answer from the options given below

1

Both Statement I and Statement II are false

2

Statement I is true but Statement II is false

3

Both Statement I and Statement II are true

4

Statement I is false but Statement II is true