Fluid Mechanics for Chemical Quiz 3

1 / 50

Cp/Cv is termed as___________?

Adiabatic constant

Mach number

Prandtl number

Weber number

2 / 50

Dimension of surface tension is (where, F = force, L = length) ?

FL-1

F-1. L

F-2. L

F.L-2

3 / 50

Diaphragm pumps are used to transport__________?

Fluids

Liquids

Solids

Slurries

4 / 50

Check valves are used________?

For controlling water flow

For unidirectional flow

At high pressure

In bends

5 / 50

Centrifugal pump is normally classified on the basis of the_________?

Type of casing

Number of blades in impeller

rpm

Impeller blade angle

6 / 50

Brownian movement is prominent in the particle size range of ______ microns in case of settling of a particle in a fluid?

100 to 1000

200 to 300

2 to 3

0.01 to 0.10

7 / 50

Cocks are used to control _____?

Any liquid

Water

Solids

None of these

8 / 50

Choose the set of pressure intensities that are equivalent ?

10 psi, 19.7 ft. of water, 5.3 inches of Hg

4.33 psi, 10 ft. of water, 8.83 inches of Hg

10 psi, 19.7 ft. of water, 23.3 inches of Hg

4.33 psi, 10 ft. of water, 20.7 inches of Hg

9 / 50

Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(?/D) + (1.26/NRe ?F). It reduces to Nikuradse equation for a value of (?/D) equal to ___________?

0.5

10 / 50

Cavitation occurs in a centrifugal pump when the suction pressure is_________?

Equal to the developed head

Greater than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Less than the vapour pressure of the liquid at that temperature

11 / 50

Buckingham-? theorem states that in any physical problem including ?n? quantities having ?m? dimensions, the quantities can be arranged into ______ independent dimensionless parameters?

n/m

n-m

12 / 50

Cd for the orifice plate varies from _____?

0.58 to 0.8

0.2 to 0.3

0.93 to 0.98

0.02 to 0.03

13 / 50

Buoyant force___________?

Depends on the weight of the floating body

None of these

For non-symmetrical bodies is not vertical

Depends on the depth of the submergence of the floating body

14 / 50

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the________?

Flow of liquid during operation of the pump

Back flow of fluid in the event of stoppage of pump

Discharge pressure

All A., B. and C.

15 / 50

Check valve is used for _________ flow?

Unidirectional

None of these

Very precise control of

Multidirectional

16 / 50

Dean number is concerned with the______?

Fluid-particle interaction

Fluid flow through helical pipes

Power consumption in agitated vessels

Psychrometry

17 / 50

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid_________?

Lies above the centroid of the plane surface

Is different for different fluids

Is independent of the specific weight of the fluid

Is at the centroid of the plane surface

18 / 50

Capacity of a rotary gear pump can be varied by___________?

Bleeding air into suction

Changing the speed of rotation

Bypassing liquid from the suction or discharge line

All A., B. and C.

19 / 50

Diaphragm valves are used for handling ________ fluids?

Non-Newtonian

Solid suspended

Corrosive

Viscous

20 / 50

Cavitation can be prevented by_________?

Maintaining suction head lower than the vapour pressure

Suitably designing the pump

Maintaining suction head = developed head

Maintaining the suction head sufficiently greater than the vapour pressure

21 / 50

Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?

f1 = f2

f1 < f2

f1 > f2

Data not sufficient to relate f1 & f2

22 / 50

Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about___________?

0.42

0.98

0.82

0.62

23 / 50

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

Increase in thrust

Develops high pressure

Decrease in effect

Develops noise

24 / 50

Creeping flow around a sphere is defined, when particle Reynolds number is_____?

< 500

< 0.1

< 2100

> 2.5

25 / 50

Centre of pressure in an immersed body is _______ the centre of gravity?

Either above or below; depends on the liquid density

Below

Above

26 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Do not need priming

Can be run with discharge line valve closed for a short interval

Run at a lower speed for the same discharge

Deliver fluid with pulsating/fluctuating discharge

27 / 50

Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.) ?

d1/3

d2/3

28 / 50

Design of the casing of centrifugal pump should be such as to minimise the_________?

Back flow through impeller

None of these

Loss of kinetic head

Loss of static head

29 / 50

Differential manometer measures the_____?

Gauge pressure

Absolute pressure

Pressure gradient

Pressure difference

30 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

None of these

Restriction in flow cross-section area occurs

Valve is closed in the line

31 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Pseudo plastic fluid

Dilatent fluid

Ideal plastic

32 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Require less space

All A., B. and C.

Have quieter operation

Have lower operating costs

33 / 50

Centrifugal pump can?t be used to pump _______?

Moderately viscous vegetable oil used in soap industry

None of the above

Thick molten soap at 80?C

Molten sodium (used as a coolant in Fast Breeder Reactor)

34 / 50

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, ? = surface tension of mercury)______?

1/d

1/?

35 / 50

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the ________ decreases?

All A., B. and C.

BHP required by the pump

NPSH required

Head of the liquid pumped

36 / 50

Differential manometer measures the______?

Atmospheric pressure

Sub-atmospheric pressure

Pressure difference between two points

None of these

37 / 50

Deformation drag, which is caused by widespread deformation of fluid around the immersed body______?

Depends mainly on cross-sectional shape

Is independent of body length

Is primarily a friction drag

Occurs when NRe is very small

38 / 50

Capacity of a hydraulic accumulator is defined in terms of maximum_______?

Rate of falling of ram

Flow rate through accumulator

Amount of energy stored

Volume available in the cylinder

39 / 50

Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively) ?

F-1L2T-1, MLT-3

FL-2T, ML-1T-1

FLT, ML-1T-1

ML-1T-3, F-1L2T

40 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T-1

L2T-2

L2T

41 / 50

Check in a centrifugal pump is_________?

Generally a globe valve

All A., B. and C.

Provided in the discharge line

Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running

42 / 50

Capillary tube method of viscosity measurement is based on the _________?

Stoke?s law

None of these

Navier-stokes equation

Hagen-Poiseuille?s equation

43 / 50

Boundary layer separation occurs when the______?

Velocity of sound is reached

Cross-section of the channel is reduced

Pressure reaches a minimum

Valve is closed in a pipeline

44 / 50

Dimension of absolute viscosity is__________?

MLT-1

ML-1T

MLT

ML-1T-1

45 / 50

Co-efficient of velocity is _____ the coefficient of discharge?

Equal to

More than

Not related to

Less than

46 / 50

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.) ?

d2/3

d4/5

d1/3

47 / 50

Cd is always _______ Cc?

Equal to

Greater than

Either more or less than

Less than

48 / 50

Cavitation in a centrifugal pump can be avoided by keeping the___________?

Outlet pressure low

Inlet pressure low

Outlet pressure high

Inlet pressure high

49 / 50

Disc compensators are provided in large diameter fuel gas carrying pipelines to__________?

Make the pipe joint leak-proof

Account for the pressure variation side the pipeline

Account for contraction/expansion of pipe due to temperature changes of the surroundings

Keep the pipe in proper orientation

50 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

Increases as fluid viscosity increases

None of these

Increases as pipe diameter increases

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