#### Chemical Engineering MCQs – Fluid Mechanics MCQs Competitive

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#### Latest Chemical Engineering MCQs

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**Latest** Fluid Mechanics Mcqs

The most occurred **mcqs of Fluid Mechanics **in past papers. **Past papers of Fluid Mechanics **Mcqs. **Past papers of** **Fluid Mechanics **Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related **Fluid Mechanics** Mcqs. The Important series of **Fluid Mechanics** Mcqs are given below:

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

**A. 0.01 to 0.1**

B. 2 to 10

C. 0.1 to 2

D. 10 to 100

**Purpose of relief valve in a reciprocating pump is to___________________?**

**A. Protect the pump against developing excessive pressure**

B. Reduce the discharge pressure

C. Facilitate unidirectional flow of liquid

D. Control the rate of discharge

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

A. Root mean square of velocity fluctuations in the three co-ordinate directions **B. Mean square of velocity fluctuations in the three co-ordinate directions**

C. Temporal velocity components

D. None of these

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

A. 50 **B. 10**

C. 5

D. 100

**Which of the following facilitates close control of flow of fluids ?**

A. Butterfly valve **B. Globe valve**

C. Gate valve

D. Check valve

**Lower BWG means _____________ of the tube?**

A. Outer diameter **B. Lower cross-section**

C. Lower thickness

D. Inner diameter

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

A. V-0.2

B. V1.8

C. V2.7**D. V2**

**Centrifugal pumps as compared to reciprocating pumps__________________?**

A. Do not need priming

B. Run at a lower speed for the same discharge

C. Deliver fluid with pulsating/fluctuating discharge**D. Can be run with discharge line valve closed for a short interval**

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

A. 500 **B. 50**

C. 5

D. 5000

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

A. Remain same **B. Decreases**

C. Increases

D. May increase or decrease

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

A. Shear force

B. Shear stress **C. Average drag per unit projected area**

D. None of these

**In continuous fluidisation_________________?**

**A. Solids are completely entrained**

B. There is no entrainment of solids

C. The pressure drop is less than that for batch fluidisation

D. Velocity of the fluid is very small

**In a free vortex, the_____________________?**

**A. Velocity changes linearly with radial distance**

B. Radial component of velocity is same everywhere

C. Flow is necessarily rotational

D. Stream lines are not circular

**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. 3y/4

D. 1/(y/4)

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

A. Hagen-Poiseuille’s **B. Ergun’s**

C. Fanning’s

D. None of these

**Air vessel of a reciprocating pump is initially filled with___________________?**

A. Water **B. Compressed air**

C. Atmospheric air

D. None of these

**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. 11.8 m **B. 11 m**

C. 10 m

D. 30 m

**Fanning friction factor equation applies to the _____________ fluid flow?**

A. Compressible

B. Non-isothermal condition of

C. Both A. and B.**D. Neither A. nor B.**

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

**A. 98**

B. 196

C. 147

D. 49

#### Chemical Engineering Basics Mcqs

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

A. 0.5

B. 0.25

C. 0.66**D. 0.95**

**Air vessel fitted to a reciprocating pump____________________?**

A. Causes cavitation **B. Decreases the work done**

C. Increases the work done

D. Results in non-uniform discharge

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

A. Leva’s **B. Blake-Plummer**

C. Kozeny-Carman

D. Hagen-Poiseuille’s

**The ______________ pressure is measured by a static tube?**

A. Total **B. Static**

C. Dynamic

D. None of these

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

A. Static

B. Accelerating frictionless

C. Uniformly moving**D. None of these**

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

A. Piston

B. Centrifugal **C. Plunger**

D. Vane

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

A. Venturimeter **B. Pitot tube**

C. Rotameter

D. Flow nozzle

**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. Bingham plastic

C. Pseudo-plastic

D. Newtonian

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

A. Incompressible

B. Irrotational

C. Viscous**D. All A., B. & C.**

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

**A. Increase**

B. Not change

C. Decrease

D. Exponentially decrease

**Newton’s law of viscosity relates the____________________?**

A. Velocity gradient and pressure intensity

B. Shear stress and velocity **C. Shear stress and rate of angular deformation in a fluid**

D. Pressure gradient and rate of angular deformation

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

A. Orificemeter

B. Venturimeter **C. Rotameter**

D. Flow nozzle

**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. d2

B. d

C. d4**D. d̅ 2**

**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. Hyperbolic **B. Parabolic**

C. Logarithmic

D. Linear

**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/4L

B. D Δp/8L **C. 8 Vavg/D**

D. 4 Vavg/D

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

A. 0.66 **B. 1**

C. 0.5

D. < 0.5

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

**A. 0.44**

B. 4.4

C. 0.044

D. 44

**In parallel pipe problems, the__________________?**

**A. Head loss is the same through each pipe**

B. Total head loss is equal to the sum of the head losses through each pipe

C. Discharge is the same through all the pipes

D. None of these

**A tube is specified by its____________________?**

A. Outer diameter only

B. Thickness only **C. Thickness & outer diameter both**

D. Inner diameter

**Poise is converted into stoke by ___________________?**

A. Multiplying with specific gravity **B. Dividing by density (gm/c.c)**

C. Multiplying with density (gm/c.c)

D. Dividing by specific gravity

**Slurries can be most conveniently pumped by a _______________ pump?**

A. Reciprocating

B. Screw

C. Gear**D. Centrifugal**

**I.D. of 1/4″ schedule 40 pipe is 0.364″. I.D. of a 1/2″ schedule 40 pipe would be ______________ inch?**

A. 0.5

B. 4.728 **C. 0.622**

D. 0.474

**Which of the following is most prone to pulsating discharge flow ?**

A. Reciprocating pump

B. Centrifugal pump **C. Gear pump**

D. Axial flow pump

**A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute ?**

**A. 500**

B. 1000

C. 200

D. 750

**Discharge in laminar flow through a pipe varies________________?**

**A. As the square of the radius**

B. Inversely as the viscosity

C. Inversely as the pressure drop

D. As the square of the diameter

**Self-priming centrifugal pump can be used for________________?**

A. Pumping industrial wastes

B. Pumping liquid fertilisers (e.g. liquid NH3)

C. Booster service **D. All A., B. and C.**

#### Chemical Heat Transfer Mcqs

**In deriving Bernoulli’s equation, fluid is assumed to be________________?**

**A. Incompressible, frictionless, steady, along a streamline**

B. Steady, density being pressure dependent, frictionless

C. Uniform, steady, incompressible, along a streamline

D. None of these

**Equivalent length of a pipe fitting is____________________?**

**A. Dependent on Reynolds number**

B. Dependent on the length of the pipe

C. Independent of Reynolds number

D. None of these

**Reynolds number for flow of water at room temperature through 2 cm dia pipe at an average velocity of 5 cm/sec is around________________?**

A. 2000

B. 100

C. 10 **D. 1000**

**In the complete turbulence zone (in rough pipes), the____________________?**

A. Laminar film covers the roughness projections

B. Rough and smooth pipes have the same friction factor

C. Friction factor depends upon NRe only**D. Friction factor is independent of the relative roughness**

**What is the value of Fanning friction factor f ‘ for smooth pipe at NRe = 106 approximately ?**

**A. 0.003**

B. 0.1

C. 0.01

D. 0.3

**For turbulent flow of an incompressible fluid through a pipe, the flow rate „Q‟ is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent ‘n’ is_________________?**

A. 0

B. 1 **C. < 1**

D. > 1

**The boundary layer is that part of a moving fluid, in which the fluid velocity is_________________?**

A. Constant

B. Affected by the fluid flow pressure **C. Affected by the presence of a solid boundary**

D. All A., B. and C.

**In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow ?**

A. Water discharge from a vertical vessel in which constant level is maintained **B. Water flow in the suction and discharge pipe of a reciprocating pump**

C. Discharge of water by a centrifugal pump being run at a constant rpm

D. Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

**Which of the following is the most common pump for pumping either raw sewage or sludge ?**

A. Centrifugal pump

B. Electromagnetic pump **C. Reciprocating pump**

D. Gear pump

**In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes_______________?**

A. More than liquid vapor pressure

B. Less than atmospheric pressure **C. Less than liquid vapor pressure**

D. More than atmospheric pressure

**When the water is warm, the height to which it can be lifted by a pump_________________?**

A. Increases due to increased vapour pressure **B. Decreases due to reduced vapour pressure**

C. Decreases due to reduced viscosity

D. Decreases due to increased frictional resistance

**Pressure drop in a fluidised bed reactor is ______________ that in a similar packed bed reactor?**

A. Same as **B. Greater than**

C. Less than

D. None of these

**In which of the following body shapes, the pressure drag is large compared to the friction drag ?**

A. Two dimensional body

B. Stream line body **C. Bluff body**

D. None of these

**Which of the following is a Newtonian fluid ?**

A. Sewage sludge

B. Rubber latex

C. Quicksand**D. Non-colloidal solution**

**In magnetic flow meters, voltage generation is________________?**

A. Proportional to the fluid velocity

B. Due to the motion of conducting fluid through an externally generated uniform field **C. Both A. and B.**

D. Neither A. nor B.

**The pressure co-efficient is the ratio of pressure forces to ______________ forces?**

**A. Viscous**

B. Gravity

C. Inertial

D. Surface tension

**Prandtl mixing length is___________________?**

A. A universal constant

B. Applicable to laminar flow problems **C. Zero at the pipe wall**

D. None of these

**Viscosity of water at 40°C lies in the range of___________________?**

A. 1 to 2 kg/m.s **B. 0.5 × 10-3 to 1 × 10-3 kg/m.s**

C. 1 × 10-3 to 2 × 10-3 kg/m.s

D. 0.5 to 1 kg/m.s

**Potential flow is characterised by the___________________?**

**A. Irrotational and frictionless flow**

B. Formation of eddies within the stream

C. One in which dissipation of mechanical energy into heat occurs

D. Irrotational and frictional flow

**Applicability of Bernoulli’s equation is limited to a/an _____________ fluid, that does not exchange shaft work with the surroundings?**

A. Non-viscous

B. Incompressible **C. Both A. and B.**

D. Neither A. nor B.

**The equation relating friction factor to Reynold number, f-0.5 = 4 loge (NRe/√f)-0.4, is called the _____________ equation?**

**A. Nikuradse**

B. Blasius

C. Von-Karman

D. Colebrook

**Which of the following relationship is valid for the equilibrium position of the float in a Rotameter? (Where, Df= Drag force on the float Bf = Buoyant force on the float Wf = Weight of the float)?**

**A. Df + Bf = Wf**

B. Df + Bf + Wf =0

C. Df = Bf + Wf

D. None of these

**Fluid resistance to shear depends upon its_______________?**

A. Cohesion

B. Rate of transfer of molecular momentum **C. Both A. and B.**

D. Neither A. nor B.

#### Chemical Reaction Mcqs

**Forces acting on a particle settling in fluid are _____________ forces?**

A. Centrifugal & drag

B. Gravitational & buoyant **C. Gravitational or centrifugal buoyant drag**

D. External, drag & viscous

**The ratio of the depth of flow to the diameter of the channel for maximum discharge in a circular channel in open channel flow is________________?**

A. 0.55

B. 0.1 **C. 0.95**

D. 1.85

**In case of turbulent flow of fluid through a circular pipe, the __________________?**

A. Velocity profile becomes flatter and flatter with increasing Reynolds number

B. Mean flow velocity is about 0.5 times the maximum velocity

C. Point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius)**D. Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more**

**The ratio of pressure forces to inertial forces is called the _______________ number?**

A. Reynold **B. Euler**

C. Froude

D. Mach

**A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by________________?**

A. Decreasing the size of the inlet pipe

B. Lowering the pump position

C. Increasing the size of the inlet pipe **D. Both B. and C.**

**A hydraulic accumulator comprises of__________________?**

A. Two pistons and two cylinders **B. A cylinder and a plunger**

C. A storage device and a control valve

D. A storage tank and a ram pump

**Fanning friction factor for laminar flow of fluid in a circular pipe is____________________?**

A. Inversely proportional to Reynolds number

B. Not a function of the roughness of pipe wall **C. Both A. & B.**

D. Neither A. nor B.

**In laminar flow through a round tube, the discharge varies ______________________?**

A. Inversely as the pressure drop

B. Linearly as the viscosity **C. Inversely as the viscosity**

D. As the square of the radius

**The ratio of inertial forces to viscous forces is called the ______________ number?**

A. Mach

B. Weber

C. Froude**D. Reynold**

**Which of the following can be used to create a flow of gas, where no significant compression is required ?**

A. Axial flow compressor **B. Blower**

C. Reciprocating compressor

D. Centrifugal compressor

**In case of a pipe exit fitted with a nozzle, the____________________?**

A. Conversion of pressure head to kinetic head is facilitated

B. Conversion of kinetic head to pressure head is facilitated

C. Power transmitted through the nozzle is maximum, when the head lost due to friction in thepipe is equal to one third of the total supply head**D. Both B. and C.**

**With increase in molecular weight of the gas, the head developed by a centrifugal compressor will________________?**

**A. Decrease**

B. Remain same

C. Increase

D. Unpredictable

**One poise (unit of absolute/dynamic viscosity) is equivalent to one_____________________?**

A. cm2/sec **B. gm/cm. sec**

C. gm/cm2. sec

D. m2/sec

**Drag is defined as the force exerted by the___________________?**

A. Solid on the fluid **B. Fluid on the solid in the direction of flow**

C. Fluid on the solid in a direction opposite to flow

D. None of these

**Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m) ________________?**

A. N2D3

B. N2D

C. ND2 **D. N3D5**

**A relief valve__________________?**

A. Unloads a pump

B. Provides back pressure for a cylinder **C. Is a directional control valve**

D. None of these

**Function of air vessel provided in a reciprocating pump is to_________________?**

**A. Reduce discharge fluctuation**

B. Avoid the necessity of priming

C. Reduce the danger of cavitation

D. Increase the pump efficiency

**Low specific speed of a pump implies that, it is a/an ______________ pump?**

A. Mixed flow **B. Centrifugal**

C. Axial flow

D. None of these

**Actual lift of a pump is always less than the theoretical lift and is limited by the__________________________?**

A. Leakage & pressure decreasing at higher elevations

B. Specific gravity & temperature of the liquid

C. Frictional resistance through pipes, fittings & passages**D. All A., B. and C.**

**Mach number is the ratio of the speed of the _____________________?**

A. Light to that of the fluid

B. Fluid to that of the light **C. Fluid to that of the sound**

D. Sound to that of the fluid

**What type of motion the fluid element undergoes, when it changes from one position to another position, such that the angle between the two sides changes ?**

A. Translation

B. Rotation

C. Linear deformation**D. Angular deformation**

**In a fluidised bed reactor___________________?**

A. Hot spots are formed **B. Temperature is more or less uniform**

C. Temperature gradients are very high

D. Segregation of the solids occurs

**For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the___________________?**

**A. Square of the radial distance**

B. Inverse of the radial distance

C. Radial distance linearly

D. Elevation along vertical direction

**For a given fluid flow rate, which of the following incurs maximum head loss ?**

**A. Orificemeter**

B. Flow nozzle

C. Venturimeter

D. All of them incur the same head loss

**With the increase in depth, the hydrostatic pressure in an un-accelerated incompressible fluid (in a constant gravitational field) ?**

A. Increases exponentially **B. Increases linearly**

C. Decreases

D. Remain constant

**Pressure drop for turbulent fluid flow through a circular pipe is given by_________________?**

A. 32μLV/gc.D2

B. 64/Re **C. 4f (L/D) (v2/2gc). ρ**

D. f (L/D) (v2/2gc). ρ

**An isentropic process is the one, in which_________________?**

A. pvr= constant

B. pv = constant **C. pvr = constant, and process is reversible**

D. None of these

**A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is___________________?**

A. 14.1

B. 5

C. 56.22**D. 28.2**

**The speed of a sound wave in a gas is analogous to the speed of ______________________?**

**A. An elementary wave in an open channel**

B. A disturbance travelling upstream in moving fluid

C. Flow in an open channel

D. None of these

**Which of the following is used for very accurate measurement of flow of gas at low velocity ?**

A. Rotameter

B. Pitot tube

C. Segmental orificemeter**D. Hot wire anemometer**

**Which law/principle of solid mechanics is similar/equivalent to Newton’s law of viscosity in fluid mechanics ?**

A. Newton’s second law of motion

B. Archimedes principle **C. Hooke’s law**

D. Newton’s third law of motion

**Pick out the correct statement pertaining to transition/ entrance length in fluid flow ?**

A. Transition length for turbulent flow of Newtonian fluids in a smooth pipe of diameter ‘d’ is equal to 50 D

B. Transition length for laminar flow of Newtonian fluids in a pipe of diameter ‘d’ is equal to 0.05. D.NRe

C. The length of entrance region of pipe, in which full development of fluid flow takes place such that velocity profile does not change downstream, is called the transition length **D. All A., B. and C.**