Fluid Mechanics MCQs Set-1

Page 1 of 4

1.

A liquid undergoing a rigid body rotation in a container is said to have

free vortex motion

Forced vortex motion

circulation

translation

2.

Pseodo plastic is a fluid for which

dynamic viscosity decreases as the rate of shear increases

Newton's law of viscosity holds good

dynamic viscosity increases with the time for which shearing forces are applied

dynamic viscosity increases as the rate of shear increases

3.

The hydraulic jump always occurs from

below critical depth to above critical depth

above normal depth to below normal depth

below critical depth to above normal depth

above critical depth to below critical depth

4.

Surface tension is due to

the difference between cohesion and adhesion

cohesion

adhesion

viscous force

5.

In a Sutro weir, the discharge is proportional to

where H is Head.

H

H^1/2

H^5/2

H^3/2

6.

Which of the following is used to measure the discharge?

pitot tube

venturimeter

current meter

hotwire anemometer

7.

What are the forces that influence the problem of fluid statics?

viscous and surface tension forces

gravity and surface tension forces

gravity and pressure forces

gravity and viscous forces

8.

An ideal fluid

is non-viscous

obey's the Newton's law of viscosity

satisfies the relation PV=RT

is both incompressible and non-viscous

9.

The fluid which obey's the Newton's law of viscosity

is called

Bingham plastic

Real fluid

Newtonian fluid

Perfect fluid

10.

The eddy viscosity for turbulent flow is

dependent on the flow

independent of the flow

a physical property of the fluid

a function of temperature only

Page 2 of 4

11.

The pressure rise due to water hammer depends upon

Time taken to close the valve

All of these

Length of pipe

Velocity of flow of water in pipe

12.

The pitot tube is used to measure

dynamic pressure

velocity at stagnation point

static pressure

stagnation pressure

13.

The pressure at the summit of a syphon is

more than atmospheric

none of these

less than atmospheric

equal to atmospheric

14.

A perfect fluid is

the one which obeys perfect gas laws

incompressible and frictionless

compressive and gaseous

a real fluid

15.

The major loss of energy in long pipes is due to

sudden enlargement

friction

gradual contraction or enlargement

sudden contraction

16.

Which one of the following is correct dimension of surface tension

J/m

J/m²

W/m

N/m²

17.

The speed of a pressure wave through a pipe depends upon

the length of pipe

the original head

the viscosity of fluid

the bulk modulus for the fluid

18.

In steady flow of a fluid, the total acceleration of any fluid particle

is never zero

is always zero

is independent of coordinates

can be zero

19.

Which is the best hydraulic section of the following open channel cross-sections?

trapezoidal

triangle

semi-circle

rectangle

20.

The surface tension of mercury at normal temperature is ____________ that of water.

same as

lower than

higher than

none of these

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21.

The property, which characterizes the resistance which a fluid offers to applied shear force is called as

relative density

viscosity

elasticity

fluidity

22.

Equation of continuity is based on the principle of conservation of

mass

none of these

energy

momentum

23.

The difference of pressure between the inside and outside the soap bubble is

2σ/d

4σ/d

8σ/d

6σ/d

24.

The best hydraulic channel cross-section is the one which has a

minimum roughness coefficient

least cost

maximum area for a given flow

minimum wetted perimeter

25.

Which one of the following is correct? the capillary rise on depression in a small diameter tube is

directly proportional to the surface area

directly proportional to the specific weight of the fluid

inversely proportional to the surface tension

inversely proportional to the diameter

26.

What is the unit of dynamic viscosity of a fluid termed 'poise' equivalent to?

gs/cm

dyne-s/cm^2

dyne/cm^2

g-cm/s

27.

The losses are more in

transition flow

laminar flow

turbulent flow

critical flow

28.

Hydraulic jump is a

i) steady flow

ii) uniform flow

iii) unsteady flow

iv) non-uniform flow

The correct answer is

(ii) and (iii)

(i) and (ii)

(iii) and (iv)

(i) and (iv)

29.

Fluid is a substance which offers no resistance to change of

flow

volume

shape

pressure

30.

Hot wire anemometer is used to measure

pressure intensity of gas

pressure intensity of liquid

discharge

velocity of gas

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31.

Capillary action is due to the

viscosity of liquid

surface tension

cohesion of liquid particles

adhesion of liquid particles on the surface

32.

Dynamic viscosity has the dimension as

L²T^-¹

ML^-2

ML^-¹T^-¹

ML^-2T^-2

33.

The hydraulic grade line is

never above the energy grade line

always above the centre line of pipe

always sloping downward in the direction of flow

all of these

34.

Fluid statics deals with

Viscous and pressure force

Gravity and pressure force

Viscous and gravity force

Surface tension and gravity force

35.

An oil of specific gravity 0.9 has viscosity of 0.28 stoke at 38 degree C. What will be its viscosity in N-s/m^2 ?

0.2520

0.0252

0.0311

0.0206

36.

What is the dimensions of kinematic viscosity of a fluid

L²T ^-¹

L²T ^-2

L¹T ^-¹

ML²T ^-¹

37.

If the surface tension of water air interface is 0.073 N/m, the gauge pressure inside a rain drop of 1 mm diameter will be

292 N/m^2

146 N/m^2

0.146 N/m^2

73 N/m^2

38.

In a forced vortex motion, the velocity of flow is

directly proportional to the square of its radial distance from the axis of rotation

directly proportional to its radial distance from axis of rotation

inversely proportional to its radial distance from axis of rotation

inversely proportional to the square of its radial distance from the axis of rotation

39.

A real fluid is any fluid which

has constant viscosity and density

has viscosity

has zero shear stress

has surface tension and is compressible

40.

Coefficient of velocity of venturimeter

is independent of Reynolds number

none of these

is equal to the coefficient of discharge of venturimeter

decreases with higher Reynolds number

Fluid Mechanics MCQs Set-1

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