Fluid Mechanics MCQs Set-1

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1.

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

dyne/cm^2

dyne-s/cm^2

g-cm/s

gs/cm

2.

The major loss of energy in long pipes is due to

sudden contraction

friction

sudden enlargement

gradual contraction or enlargement

3.

Hot wire anemometer is used to measure

pressure intensity of gas

velocity of gas

discharge

pressure intensity of liquid

4.

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

0.0206

0.0311

0.0252

5.

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

is never zero

is independent of coordinates

is always zero

can be zero

6.

A real fluid is any fluid which

has constant viscosity and density

has surface tension and is compressible

has viscosity

has zero shear stress

7.

Dynamic viscosity has the dimension as

ML^-¹T^-¹

ML^-2T^-2

ML^-2

L²T^-¹

8.

Hydraulic jump is a

i) steady flow

ii) uniform flow

iii) unsteady flow

iv) non-uniform flow

The correct answer is

(i) and (iv)

(iii) and (iv)

(i) and (ii)

(ii) and (iii)

9.

The losses are more in

transition flow

turbulent flow

laminar flow

critical flow

10.

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

directly proportional to the surface area

inversely proportional to the surface tension

directly proportional to the specific weight of the fluid

inversely proportional to the diameter

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11.

The hydraulic grade line is

always above the centre line of pipe

never above the energy grade line

always sloping downward in the direction of flow

all of these

12.

The pressure at the summit of a syphon is

none of these

less than atmospheric

more than atmospheric

equal to atmospheric

13.

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

relative density

fluidity

viscosity

elasticity

14.

The eddy viscosity for turbulent flow is

a physical property of the fluid

a function of temperature only

dependent on the flow

independent of the flow

15.

Which one of the following is correct dimension of surface tension

W/m

J/m

N/m²

J/m²

16.

In a Sutro weir, the discharge is proportional to

where H is Head.

H^3/2

H^5/2

H^1/2

H

17.

What is the dimensions of kinematic viscosity of a fluid

L¹T ^-¹

L²T ^-2

L²T ^-¹

ML²T ^-¹

18.

The pitot tube is used to measure

velocity at stagnation point

static pressure

dynamic pressure

stagnation pressure

19.

A perfect fluid is

the one which obeys perfect gas laws

compressive and gaseous

incompressible and frictionless

a real fluid

20.

The hydraulic jump always occurs from

below critical depth to above critical depth

above critical depth to below critical depth

above normal depth to below normal depth

below critical depth to above normal depth

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21.

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

is called

Newtonian fluid

Bingham plastic

Perfect fluid

Real fluid

22.

The speed of a pressure wave through a pipe depends upon

the viscosity of fluid

the length of pipe

the original head

the bulk modulus for the fluid

23.

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

Forced vortex motion

free vortex motion

translation

circulation

24.

In a forced vortex motion, the velocity of flow is

inversely 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

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

25.

Pseodo plastic is a fluid for which

dynamic viscosity decreases as the rate of shear increases

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

dynamic viscosity increases as the rate of shear increases

Newton's law of viscosity holds good

26.

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

viscous and surface tension forces

gravity and pressure forces

gravity and surface tension forces

gravity and viscous forces

27.

Coefficient of velocity of venturimeter

none of these

decreases with higher Reynolds number

is independent of Reynolds number

is equal to the coefficient of discharge of venturimeter

28.

Fluid is a substance which offers no resistance to change of

flow

shape

pressure

volume

29.

Equation of continuity is based on the principle of conservation of

energy

momentum

none of these

mass

30.

Capillary action is due to the

adhesion of liquid particles on the surface

surface tension

viscosity of liquid

cohesion of liquid particles

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31.

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

8σ/d

4σ/d

6σ/d

2σ/d

32.

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

maximum area for a given flow

minimum roughness coefficient

least cost

minimum wetted perimeter

33.

Surface tension is due to

adhesion

the difference between cohesion and adhesion

viscous force

cohesion

34.

An ideal fluid

obey's the Newton's law of viscosity

is non-viscous

is both incompressible and non-viscous

satisfies the relation PV=RT

35.

Which of the following is used to measure the discharge?

current meter

venturimeter

pitot tube

hotwire anemometer

36.

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

triangle

trapezoidal

semi-circle

rectangle

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

73 N/m^2

0.146 N/m^2

146 N/m^2

292 N/m^2

38.

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

lower than

higher than

same as

none of these

39.

Fluid statics deals with

Viscous and pressure force

Surface tension and gravity force

Gravity and pressure force

Viscous and gravity force

40.

The pressure rise due to water hammer depends upon

Velocity of flow of water in pipe

All of these

Time taken to close the valve

Length of pipe

Fluid Mechanics MCQs Set-1

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