Physics Fluid Dynamic MCQs Chapter 6 Class 11 - PLS Academy

Physics Fluid Dynamics for First Year Entry Tests and FSC Board Exams

Fluid Dynamics is a fundamental chapter in First Year Physics that explains the behavior of liquids and gases in motion. Therefore, it plays an important role in preparation for MDCAT, NUMS, AKU, NUST, UET ECAT, and FSC First Year board examinations. This chapter covers key concepts such as flow rate, continuity equation, Bernoulli’s principle, pressure variations, and viscosity. Since these topics appear frequently in MCQs and numericals, students must understand them clearly.

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Created on February 07, 2022 By Ali Durrani

Physics Ch 6 Class 11 Fluid Dynamics

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1 / 33

The product of cross-sectional area of the pipe and the fluid speed at any point along the pipe:

UHS 2013
Physics
Fluid Dynamics
Elimination Tool:

A) Remains constant

B) Is zero

C) Exponentially increases

D) Exponentially decreases

2 / 33

How much more thumb pressure must a nurse use to administer an injection with a hypodermic needle of inside diameter 0.30 mm compared to one with inside diameter 0.60 mm? Assume that the two needles have the same length and that the volume flow rate is the same in both cases.

NUMS 2015
Physics
Fluid Dynamics
Elimination Tool:

A) Twice as much

B) 4 times as much

C) 8 times as much

D) 16 times as much

3 / 33

Mass flow per second of the fluid is given by:

UHS 2015
Physics
Fluid Dynamics
Elimination Tool:

A) ρAv

B) Av

C) ρv

D) Av/ρ

4 / 33

When the drag force is equal to the weight of the droplet, the droplet will fall with:

UHS 2011
Physics
Fluid Dynamics
Elimination Tool:

A) High Speed

B) Low Speed

C) Certain acceleration

D) Constant Speed

5 / 33

A small leak is developed in a large water storage tank. If the height of water above the leakage is 10 m, then find the speed of efflux through the leak:

UHS 2013
Physics
Fluid Dynamics
Elimination Tool:

A) 14 m/sec

B) 10 m/sec

C) 9.8 m/sec

D) 20 m/sec

6 / 33

If 500 cm3 of gas, having a pressure of 760 millimeters of mercury, is compressed into a volume of 300 cm3. If the temperature remains constant, the pressure of the gas will be, in millimeters of mercury, approximately:

NTS 2017
Physics
Fluid Dynamics
Elimination Tool:

A) 500

B) 900

C) 1,100

D) 1,270

7 / 33

A maintenance crew is working on a section of a three-lane highway with only one lane open to traffic. This result is much slower traffic flow. The cars on this highway behave like:

NUMS 2015
Physics
Fluid Dynamics
Elimination Tool:

A) The molecules of an incompressible fluid

B) The molecules of a compressed fluid

C) Both (A) and (B)

D) None of the above

8 / 33

Water is flowing in a streamline motion through a horizontal tube. The pressure at a point in the tube is P where the velocity of now is v. At another point, where the pressure is P/2, the velocity of flow is: (density of water=ρ)

NUMS 2014
Physics
Fluid Dynamics
Elimination Tool:

A) √(v2 + P/ρ)

B) √(v2 – P/ρ)

C) √(v2 + 2P/ρ)

D) √(v2 – 2P/ρ)

9 / 33

In a river flow of water is maximum at

Middle

Top right corner

Top left corner

Same flow throughout

10 / 33

If the speed of efflux through a small hole in a large tank is 9.8 m/s. Find the height at the fluid above the hole:

UHS 2012
Physics
Fluid Dynamics
Elimination Tool:

A) 1 m

B) 9.8 m

C) 4.9 m

D) 19.6 m

11 / 33

A thin horizontal plate of area 0.036 m2 is beneath the surface of a liquid of density 930 kg m−3. The force on one side of the plate due to the pressure of the liquid is 290 N. What is the depth of the plate beneath the surface of the liquid?

ETEA 2018
Physics
Fluid Dynamics
Elimination Tool:

A) 0.88 m

B) 1.1 m

C) 1.8 m

D) 8.7 m

12 / 33

Flow speed of the fluid through a non-uniform pipe increases from 1 m/sec to 3 m/sec. If change in P.E. is zero, then pressure difference between two points will be: (density of the fluid = 1000 kg/m3)

UHS 2012
Physics
Fluid Dynamics
Elimination Tool:

A) 1000 N/m2

B) 9000 N/m2

C) 8000 N/m2

D) 4000 N/m2

13 / 33

What is dimension of coefficient of viscosity?

MLT

ML-1T

ML-1T-1

MLT-1

14 / 33

Two sample of gases ‘1’ and ‘2’ are taken at same temperature and pressure
but the ratio of number of their volume is V1
:V2 = 2:3. What is the ratio of the
number of moles of the gas sample?

UHS 2015
Physics
Fluid Dynamics
Elimination Tool:

A) 3:2

B) √2 :√3

C) 4:9

D) 2:3

15 / 33

S.I. Unit of rate of flow of a fluid :

NUMS 2018
Physics
Fluid Dynamics
Elimination Tool:

A) Meter / sec

B) Meter2/ sec

C) Meter3/ sec

D) Meter2/ sec2

16 / 33

A body moving on a fluid will experience:

NUMS 2016
Physics
Fluid Dynamics
Elimination Tool:

A) Drag force

B) Centripetal force

C) Centrifugal force

D) Tabular force

17 / 33

Density of blood is:

NUMS 2016
Physics
Fluid Dynamics
Elimination Tool:

A) More than water

B) less than that of water

C) Nearly equal to water

D) 3 times greater than water

18 / 33

Blood pressure of a healthy person is mm Hg.

140 / 60

120 / 80

80 / 120

90 / 60

19 / 33

If the radii of two droplets are in the ratio 2:3, what will be the ratio of their Terminal velocities?

2 : 3

4 : 6

4 : 9

2 : 6

20 / 33

If each particle of fluid is passing through the same point, what would be the flow?

NUMS 2016
Physics
Fluid Dynamics
Elimination Tool:

A) Linear

B) Streamline

C) Tubular

D) Both A and B

21 / 33

If an object sinks in the water, then

Object is denser than water

Water is denser than object

Either a or b

None

22 / 33

The density of blood is:

UHS 2011
Physics
Fluid Dynamics
Elimination Tool:

A) Less than water

B) Nearly equal to water

C) Greater than water

D) Three times that of water

23 / 33

Stokes’ Law for steady motion in a fluid of infinite extent is given by:

UHS 2012
Physics
Fluid Dynamics
Elimination Tool:

A) F = 6πηrv

B) F = (4/3)πr3ρg

C) F = 6πηr2ρ

D) F = 2gr2ρ/9η

24 / 33

Stokes’ Law is given as:

UHS 2013
Physics
Fluid Dynamics
Elimination Tool:

A) F = 6πηr2v

B) F = 6πηrv

C) F = 6πηrv-1

D) F = 6π2ηr3v

25 / 33

For the horizontal pipe, the fluid inside it is flowing horizontally then Bernoulli’s
equation can be written as

UHS 2014
Physics
Fluid Dynamics
Elimination Tool:

A) P + ρv = constant

B) 2P + ρv2 = constant

C) P + 2ρv2 = constant

D) 2P + 2ρv2 = constant

26 / 33

When fluid is incompressible, it means:

NUMS 2018
Physics
Fluid Dynamics
Elimination Tool:

A) No internal frictional force

B) Independent of coordinates

C) Independent of time

D) Its density remains constant

27 / 33

Equation of continuity is expressed as:

NUMS 2018
Physics
Fluid Dynamics
Elimination Tool:

A) A1V2 = A2V1

B) A1V1 = A2V2

C) A1H2 = A2H1

D) A1H1 = A2H2

28 / 33

An object having spherical shape of radius ‘r’ experiences a retarding force F from a fluid of coefficient of viscosity ‘η’ when moving through the fluid with speed ‘v’. What is the ratio of retarding force to speed?

UHS 2011
Physics
Fluid Dynamics
Elimination Tool:

A) 6πη r2

B) 6πη/r2

D) 6πη/r

C) 6πη r

29 / 33

Root mean square velocity of a gas having pressure ‘P’ and density ‘ρ’ is given
by:

UHS 2015
Physics
Fluid Dynamics
Elimination Tool:

A) √(3P/ρ)

B) 3Pρ

C) 3ρ/P

D) √3ρ/P

30 / 33

terminal velocity of a water droplet is dependent on:

Mass

Radius

Both a and b

None

31 / 33

Speed and Pressure relation of a fluid is given by:

Venturi relation

Stoke's Law

Equation of Continuity

Bernoulli's Equation

32 / 33

The viscous drag on small spherical body (moving with slow speed v) is propotional to

ETEA 2019
Physics
Fluid Dynamics
Elimination Tool:

A) v

B) Square root of v

C) 1/square root of v

D) v2

33 / 33

Ideal fluid is:

NUMS 2018
Physics
Fluid Dynamics
Elimination Tool:

A) Incompressible

B) Steady flow

C) Non – viscous

D) All of these

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The average score is 58%

Conceptual Importance of Fluid Dynamics in Physics

A strong grip on Fluid Dynamics helps students analyze fluid flow, calculate pressure differences, and understand energy conservation in moving fluids. Moreover, it builds a foundation for solving real-life problems related to airplanes, blood circulation, water pipes, and hydraulic systems. Concepts like streamline flow, turbulent flow, and applications of Bernoulli’s theorem are commonly tested in competitive exams. As a result, regular practice improves both speed and accuracy.

Effective Preparation Strategy for Fluid Dynamics

To prepare efficiently, students should memorize formulas, solve numerical problems, and practice chapter-wise MCQs. In addition, attempting past papers and mock tests helps in understanding exam patterns and repeated questions. PLS Academy offers structured resources that support students in mastering Fluid Dynamics for entry tests and FSC First Year examinations with confidence.

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