Fluid Mechanics Mcqs for Chemical - Set 1

1)   Stoke’s equation is valid in the Reynolds number range__________________?

a. 0.01 to 0.1
b. 0.1 to 2
c. 2 to 10
d. 10 to 100
Answer  Explanation 

ANSWER: 0.01 to 0.1

Explanation:
No explanation is available for this question!


2)   Purpose of relief valve in a reciprocating pump is to___________________?

a. Protect the pump against developing excessive pressure
b. Facilitate unidirectional flow of liquid
c. Reduce the discharge pressure
d. Control the rate of discharge
Answer  Explanation 

ANSWER: Protect the pump against developing excessive pressure

Explanation:
No explanation is available for this question!


3)   In isotropic turbulence, the _____________ are equal to each other?

a. Temporal velocity components
b. Mean square of velocity fluctuations in the three co-ordinate directions
c. Root mean square of velocity fluctuations in the three co-ordinate directions
d. None of these
Answer  Explanation 

ANSWER: Mean square of velocity fluctuations in the three co-ordinate directions

Explanation:
No explanation is available for this question!


4)   What is the maximum theoretical suction lift (metres) of a reciprocating pump ?

a. 5
b. 10
c. 50
d. 100
Answer  Explanation 

ANSWER: 10

Explanation:
No explanation is available for this question!


5)   Which of the following facilitates close control of flow of fluids ?

a. Gate valve
b. Globe valve
c. Butterfly valve
d. Check valve
Answer  Explanation 

ANSWER: Globe valve

Explanation:
No explanation is available for this question!


6)   Lower BWG means _____________ of the tube?

a. Lower thickness
b. Lower cross-section
c. Outer diameter
d. Inner diameter
Answer  Explanation 

ANSWER: Lower cross-section

Explanation:
No explanation is available for this question!


7)   Pressure drop (Δp) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as___________________?

a. V1.8
b. V-0.2
c. V2.7
d. V2
Answer  Explanation 

ANSWER: V2

Explanation:
No explanation is available for this question!


8)   Centrifugal pumps as compared to reciprocating pumps__________________?

a. Run at a lower speed for the same discharge
b. Do not need priming
c. Deliver fluid with pulsating/fluctuating discharge
d. Can be run with discharge line valve closed for a short interval
Answer  Explanation 

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

Explanation:
No explanation is available for this question!


9)   Transition length for a turbulent fluid entering into a pipe is around _____________ times the pipe diameter?

a. 5
b. 50
c. 500
d. 5000
Answer  Explanation 

ANSWER: 50

Explanation:
No explanation is available for this question!


10)   The boundary layer thickness at a given section along a flat plate _____________ with increasing Reynold’s number?

a. Increases
b. Decreases
c. Remain same
d. May increase or decrease
Answer  Explanation 

ANSWER: Decreases

Explanation:
No explanation is available for this question!


11)   Drag co-efficient for flow past immersed body is the ratio of _____________ to the product of velocity head and density?

a. Shear stress
b. Shear force
c. Average drag per unit projected area
d. None of these
Answer  Explanation 

ANSWER: Average drag per unit projected area

Explanation:
No explanation is available for this question!


12)   In continuous fluidisation_________________?

a. Solids are completely entrained
b. The pressure drop is less than that for batch fluidisation
c. There is no entrainment of solids
d. Velocity of the fluid is very small
Answer  Explanation 

ANSWER: Solids are completely entrained

Explanation:
No explanation is available for this question!


13)   In a free vortex, the_____________________?

a. Velocity changes linearly with radial distance
b. Flow is necessarily rotational
c. Radial component of velocity is same everywhere
d. Stream lines are not circular
Answer  Explanation 

ANSWER: Velocity changes linearly with radial distance

Explanation:
No explanation is available for this question!


14)   The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which “sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis”. The centre of pressure of a rectangular surface (of width ‘w’) immersed vertically in a static mass of fluid is at a depth of (where, y = depth of the liquid) ?

a. 1/(y/3)
b. 2y/3
c. 1/(y/4)
d. 3y/4
Answer  Explanation 

ANSWER: 2y/3

Explanation:
No explanation is available for this question!


15)   Fluid flow through a packed bed is represented by the ______________ equation?

a. Fanning’s
b. Ergun’s
c. Hagen-Poiseuille’s
d. None of these
Answer  Explanation 

ANSWER: Ergun’s

Explanation:
No explanation is available for this question!


16)   Air vessel of a reciprocating pump is initially filled with___________________?

a. Atmospheric air
b. Compressed air
c. Water
d. None of these
Answer  Explanation 

ANSWER: Compressed air

Explanation:
No explanation is available for this question!


17)   A centrifugal pump is used to pump water through a horizontal distance of 150 m, and then raised to an overhead tank 10 m above. The pipe is smooth with an I.D of 50 mm. What head (m of water) must the pump generate at its exit E. to deliver water at a flow rate of 0.001 m3/s? The Fanning friction factor, f is 0.0062 ?

a. 10 m
b. 11 m
c. 11.8 m
d. 30 m
Answer  Explanation 

ANSWER: 11 m

Explanation:
No explanation is available for this question!


18)   Fanning friction factor equation applies to the _____________ fluid flow?

a. Non-isothermal condition of
b. Compressible
c. Both A. and B.
d. Neither A. nor B.
Answer  Explanation 

ANSWER: Neither A. nor B.

Explanation:
No explanation is available for this question!


19)   A pressure of 10 m head of water is equivalent to ______________ kN/m2?

a. 98
b. 147
c. 196
d. 49
Answer  Explanation 

ANSWER: 98

Explanation:
No explanation is available for this question!


20)   The maximum discharge through a circular channel takes place, when the depth of the fluid flow is ______________ times the pipe diameter?

a. 0.25
b. 0.5
c. 0.66
d. 0.95
Answer  Explanation 

ANSWER: 0.95

Explanation:
No explanation is available for this question!


21)   Air vessel fitted to a reciprocating pump____________________?

a. Increases the work done
b. Decreases the work done
c. Causes cavitation
d. Results in non-uniform discharge
Answer  Explanation 

ANSWER: Decreases the work done

Explanation:
No explanation is available for this question!


22)   Pressure drop in packed bed for turbulent flow is given by the ______________ equation?

a. Kozeny-Carman
b. Blake-Plummer
c. Leva’s
d. Hagen-Poiseuille’s
Answer  Explanation 

ANSWER: Blake-Plummer

Explanation:
No explanation is available for this question!


23)   The ______________ pressure is measured by a static tube?

a. Dynamic
b. Static
c. Total
d. None of these
Answer  Explanation 

ANSWER: Static

Explanation:
No explanation is available for this question!


24)   Pascal law is not applicable for a/an ________________________ fluid?

a. Accelerating frictionless
b. Static
c. Uniformly moving
d. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
No explanation is available for this question!


25)   _____________ pump is the most suitable device for discharging a liquid against a pressure of ≥ 1500 kgf/cm2?

a. Centrifugal
b. Piston
c. Plunger
d. Vane
Answer  Explanation 

ANSWER: Plunger

Explanation:
No explanation is available for this question!


26)   In a/an _____________, the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure?

a. Rotameter
b. Pitot tube
c. Venturimeter
d. Flow nozzle
Answer  Explanation 

ANSWER: Pitot tube

Explanation:
No explanation is available for this question!


27)   The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of _____________ fluid?

a. Dilatent
b. Pseudo-plastic
c. Bingham plastic
d. Newtonian
Answer  Explanation 

ANSWER: Dilatent

Explanation:
No explanation is available for this question!


28)   Bernoulli’s equation is not applicable, when the flow is___________________?

a. Irrotational
b. Incompressible
c. Viscous
d. All A., B. & C.
Answer  Explanation 

ANSWER: All A., B. & C.

Explanation:
No explanation is available for this question!


29)   Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will _____________ the gas discharge pressure?

a. Increase
b. Decrease
c. Not change
d. Exponentially decrease
Answer  Explanation 

ANSWER: Increase

Explanation:
No explanation is available for this question!


30)   Newton’s law of viscosity relates the____________________?

a. Shear stress and velocity
b. Velocity gradient and pressure intensity
c. Shear stress and rate of angular deformation in a fluid
d. Pressure gradient and rate of angular deformation
Answer  Explanation 

ANSWER: Shear stress and rate of angular deformation in a fluid

Explanation:
No explanation is available for this question!


31)   Which is the most efficient and best for measuring very small flow rate of gases ?

a. Venturimeter
b. Orificemeter
c. Rotameter
d. Flow nozzle
Answer  Explanation 

ANSWER: Rotameter

Explanation:
No explanation is available for this question!


32)   For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as_________________?

a. d
b. d2
c. d4
d. d̅ 2
Answer  Explanation 

ANSWER: d̅ 2

Explanation:
No explanation is available for this question!


33)   For laminar flow of Newtonian fluid in a circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the centre line of the pipe, and it follows a ______________ relationship?

a. Logarithmic
b. Parabolic
c. Hyperbolic
d. Linear
Answer  Explanation 

ANSWER: Parabolic

Explanation:
No explanation is available for this question!


34)   What is the shear rate at the pipe wall, in case of laminar flow of Newtonian fluids in a pipe of diameter ‘D’ & length ‘L’ incurring a pressure drop ‘Δp’ with average velocity ‘Vavg’ ?

a. D Δp/8L
b. D Δp/4L
c. 8 Vavg/D
d. 4 Vavg/D
Answer  Explanation 

ANSWER: 8 Vavg/D

Explanation:
No explanation is available for this question!


35)   For turbulent flow of Newtonian fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is ________________?

a. 0.5
b. 1
c. 0.66
d. < 0.5
Answer  Explanation 

ANSWER: 1

Explanation:
No explanation is available for this question!


36)   In Newton’s law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is___________________?

a. 0.44
b. 0.044
c. 4.4
d. 44
Answer  Explanation 

ANSWER: 0.44

Explanation:
No explanation is available for this question!


37)   In parallel pipe problems, the__________________?

a. Head loss is the same through each pipe
b. Discharge is the same through all the pipes
c. Total head loss is equal to the sum of the head losses through each pipe
d. None of these
Answer  Explanation 

ANSWER: Head loss is the same through each pipe

Explanation:
No explanation is available for this question!


38)   A tube is specified by its____________________?

a. Thickness only
b. Outer diameter only
c. Thickness & outer diameter both
d. Inner diameter
Answer  Explanation 

ANSWER: Thickness & outer diameter both

Explanation:
No explanation is available for this question!


39)   Poise is converted into stoke by ___________________?

a. Multiplying with density (gm/c.c)
b. Dividing by density (gm/c.c)
c. Multiplying with specific gravity
d. Dividing by specific gravity
Answer  Explanation 

ANSWER: Dividing by density (gm/c.c)

Explanation:
No explanation is available for this question!


40)   Slurries can be most conveniently pumped by a _______________ pump?

a. Screw
b. Reciprocating
c. Gear
d. Centrifugal
Answer  Explanation 

ANSWER: Centrifugal

Explanation:
No explanation is available for this question!