Fluid Mechanics for Chemical Quiz 3

1 / 50

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

1/?

1/d

2 / 50

Cd is always _______ Cc?

Equal to

Greater than

Less than

Either more or less than

3 / 50

Centrifugal pump is normally classified on the basis of the_________?

rpm

Number of blades in impeller

Impeller blade angle

Type of casing

4 / 50

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

Below

Either above or below; depends on the liquid density

Above

5 / 50

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

d2/3

d1/3

6 / 50

Diaphragm valves are used for handling ________ fluids?

Solid suspended

Non-Newtonian

Viscous

Corrosive

7 / 50

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

All A., B. and C.

Flow of liquid during operation of the pump

Back flow of fluid in the event of stoppage of pump

Discharge pressure

8 / 50

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

Make the pipe joint leak-proof

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

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

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

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

More than

Not related to

Equal to

Less than

11 / 50

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

0.01 to 0.10

200 to 300

2 to 3

100 to 1000

12 / 50

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

FL-1

F-1. L

F.L-2

F-2. L

13 / 50

Capacity of a rotary gear pump can be varied by___________?

Changing the speed of rotation

All A., B. and C.

Bleeding air into suction

Bypassing liquid from the suction or discharge line

14 / 50

Cd for the orifice plate varies from _____?

0.2 to 0.3

0.93 to 0.98

0.58 to 0.8

0.02 to 0.03

15 / 50

Critical velocity in a pipe flow__________?

Independent of fluid density

Increases as pipe diameter increases

None of these

Increases as fluid viscosity increases

16 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

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

17 / 50

Centrifugal pump can?t be used to pump _______?

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

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

None of the above

18 / 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

Decrease in effect

Develops high pressure

Develops noise

19 / 50

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

None of these

Back flow through impeller

Loss of kinetic head

Loss of static head

20 / 50

Dimension of kinematic viscosity is_______?

L2T

L2T-1

MLT-1

L2T-2

21 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Valve is closed in a pipeline

Velocity of sound is reached

Cross-section of the channel is reduced

22 / 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 independent of the specific weight of the fluid

Is at the centroid of the plane surface

Is different for different fluids

23 / 50

Cocks are used to control _____?

Water

None of these

Solids

Any liquid

24 / 50

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

Less than the vapour pressure of the liquid at that temperature

Greater than the vapour pressure of the liquid at that temperature

Equal to the vapour pressure

Equal to the developed head

25 / 50

Cavitation can be prevented by_________?

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

Maintaining suction head lower than the vapour pressure

Maintaining suction head = developed head

26 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

Restriction in flow cross-section area occurs

None of these

Valve is closed in the line

27 / 50

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

Inlet pressure low

Outlet pressure low

Outlet pressure high

Inlet pressure high

28 / 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___________?

0.62

0.82

0.98

0.42

29 / 50

Diaphragm pumps are used to transport__________?

Solids

Slurries

Fluids

Liquids

30 / 50

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

Flow rate through accumulator

Volume available in the cylinder

Rate of falling of ram

Amount of energy stored

31 / 50

Check valves are used________?

In bends

For unidirectional flow

For controlling water flow

At high pressure

32 / 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

33 / 50

Cp/Cv is termed as___________?

Weber number

Adiabatic constant

Prandtl number

Mach number

34 / 50

Check in a centrifugal pump is_________?

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

All A., B. and C.

Provided in the discharge line

Generally a globe valve

35 / 50

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

d1/3

d4/5

d2/3

36 / 50

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

< 0.1

< 2100

> 2.5

< 500

37 / 50

Dean number is concerned with the______?

Power consumption in agitated vessels

Fluid flow through helical pipes

Psychrometry

Fluid-particle interaction

38 / 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

Data not sufficient to relate f1 & f2

f1 < f2

39 / 50

Check valve is used for _________ flow?

None of these

Multidirectional

Unidirectional

Very precise control of

40 / 50

Dimension of absolute viscosity is__________?

ML-1T

ML-1T-1

MLT

MLT-1

41 / 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

Occurs when NRe is very small

Is primarily a friction drag

42 / 50

Differential manometer measures the______?

None of these

Sub-atmospheric pressure

Pressure difference between two points

Atmospheric pressure

43 / 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

FLT, ML-1T-1

FL-2T, ML-1T-1

ML-1T-3, F-1L2T

44 / 50

Buoyant force___________?

For non-symmetrical bodies is not vertical

Depends on the weight of the floating body

None of these

Depends on the depth of the submergence of the floating body

45 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have quieter operation

Require less space

Have lower operating costs

All A., B. and C.

46 / 50

Curve III in the bellow diagram represents a/an_________?

Pseudo plastic fluid

None of these

Dilatent fluid

Ideal plastic

47 / 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?

BHP required by the pump

Head of the liquid pumped

NPSH required

All A., B. and C.

48 / 50

Choose the set of pressure intensities that are equivalent ?

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

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

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

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

49 / 50

Differential manometer measures the_____?

Gauge pressure

Pressure difference

Absolute pressure

Pressure gradient

50 / 50

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

Stoke?s law

Navier-stokes equation

Hagen-Poiseuille?s equation

None of these

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