#### 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:

**Capacity of a rotary gear pump can be varied by__________________?**

A. Bleeding air into suction

B. Changing the speed of rotation

C. Bypassing liquid from the suction or discharge line**D. All A., B. and C.**

**For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of_________________?**

**A. 2**

B. 1/2

D. 2

**The valve used for very remote and accurate control of fluid is a _____________ valve?**

**A. Needle**

B. Gate

C. Globe

D. Butterfly

**If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor). ?**

**A. Q = Q1 + Q2 + Q3**

B. Q1 = Q2 = Q3

C. V1 = V2 = V3

D. f = f1 + f2 + f3

**Drag co-efficient CD, in Stoke’s law range is given by________________?**

A. CD = 18.4/Re.p **B. CD = 24/Re.p**

C. CD = 16/Re.p

D. CD = 0.079/Re.p

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

A. Loss of static head **B. Loss of kinetic head**

C. Back flow through impeller

D. None of these

**Quicksand is an example of a __________ fluid?**

A. Newtonian **B. Dilatant**

C. Bingham plastic

D. Pseudo plastic

**The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for ____________ fluid?**

A. Dilatent **B. Pseudo-plastic**

C. Newtonian

D. Bingham plastic

**The peripheral velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec?**

A. 186.2 **B. 12.4**

C. 1.8

D. 736.4

**Hot wire anemometer is used to measure the_________________?**

A. Temperature of liquids

B. Velocity of liquids **C. Velocity of gases**

D. Pressure of liquids

**The pressure intensity is the same in all directions at a point in a fluid________________?**

A. Only when the fluid is at rest having zero velocity

B. Only when the fluid is frictionless **C. When there is no motion of one fluid layer relative to an adjacent layer**

D. Regardless of the motion of one fluid layer relative to an adjacent layer

**Hydraulic mean radius for flow through packed bed of spherical particle of size, ‘Dp, with porosity ‘ε’ is________________?**

**A. (Dp/6) (ε/1- ε)**

B. ⅔Dp (1- ε/ε)

C. (Dp/6) (1- ε/ε)

D. ⅔Dp (ε/1- ε)

**Gradually varying fluid flow is an example of ____________ flow?**

**A. Non-steady uniform**

B. Steady uniform

C. Non-steady non-uniform

D. Steady non-uniform

**The head loss in turbulent flow in pipe is proportional to(where, V = velocity of fluid through the pipe) ?**

**A. V2**

B. 1/V

C. 1/V2

D. V

**Prandtl number is a measure of the__________________?**

**A. Heat conduction to viscosity of a fluid**

B. Elastic force to pressure force in the fluid flow

C. Cp/Cv of a fluid

D. Inertial force to elastic force in the fluid flow

**Potential flow is the flow of______________?**

A. Compressible fluids with no shear

B. Compressible fluids with shear

C. Incompressible fluids with shear**D. Incompressible fluids with no shear**

**Weber number is the ratio of inertial force to _____________ force?**

**A. Surface tension**

B. Viscous

C. Gravity

D. Elastic

**In case of Couette flow, the fluid flow is between two large flat parallel plates with___________________?**

**A. Top plate moving and the bottom plate fixed**

B. Bottom plate moving and the top plate fixed

C. Both the plates moving

D. Both the plates fixed

**Dimension of kinematic viscosity is_____________________?**

A. L2T **B. L2T-1**

C. MLT-1

D. L2T-2

**Multistage compressors are used in industry, because they____________________?**

A. Reduce the size requirement

B. Reduce the cost of compressor **C. Resemble closely to isothermal compression**

D. Are easy to control

#### Furnace Technology Mcqs

**Hydraulic _____________ works on the principle of Pascal’s law of transmission of fluid pressure?**

**A. Press**

B. Pump

C. Turbine

D. Coupling

**The discharge through a semi-circular weir varies as (where, H = Head of liquid.) ?**

A. H3/2 **B. H2**

C. H

D. H1/2

**Piezometric head is the sum of the ______________ heads?**

A. Kinetic energy & pressure **B. Elevation & pressure**

C. Elevation & kinetic energy

D. None of these

**Which of the following exemplifies a three dimensional fluid flow ?**

**A. Fluid flow at the inlet to a nozzle**

B. Viscous fluid flow between converging plates

C. Fluid flow between parallel plates

D. None of these

**f = 16/NRe, is valid for__________________?**

A. Laminar flow through an open channel

B. Turbulent flow

C. Steady flow**D. None of these**

**Which law is followed by the velocity distribution in the turbulent boundary layer ?**

A. Linear law

B. Parabolic law **C. Logarithmic law**

D. None of these

**In case of turbulent flow of a Newtonian fluid in a straight pipe, the maximum velocity is equal to (where, Vavg = average fluid velocity)?**

A. 1.5 Vavg **B. 1.2 Vavg**

C. Vavg

D. 1.8 Vavg

**Unsteady non-uniform flow is represented by flow through a/an_________________?**

A. Long pipe at decreasing rate

B. Long pipe at constant rate **C. Expanding tube at increasing rate**

D. Expanding tube at constant rate

**Slugging occurs in a fluidised bed, if the bed is___________________?**

A. Deep

B. Narrow **C. Both A. & B.**

D. Neither A. nor B.

**The curve of metacentre for a floating body ____________ the curve of buoyancy?**

A. Is tangential to **B. Is the evolute of**

C. Intersects at right angle

D. Is always below

**What is the ratio of total kinetic energy of fluid passing per second to the value obtained on the basis of average velocity (for laminar flow through a circular pipe) ?**

A. 0.5

B. 1.5

C. 1 **D. 2**

**Erosion and pits formation on the impeller of a centrifugal pump may be due to________________?**

**A. Cavitation**

B. Off centering of pump with motor

C. Its operation with delivery valve closed for considerable time after starting the pump

D. Low speed of impeller

**Cavitation occurs in a centrifugal pump when the suction pressure is________________?**

**A. Less than the vapour pressure of the liquid at that temperature**

B. Greater than the vapour pressure of the liquid at that temperature

C. Equal to the developed head

D. Equal to the vapour pressure

**Propellers are____________________?**

**A. Axial flow mixers**

B. Radial flow mixers

C. Used for mixing liquids of high viscosity

D. Low speed impeller

**The range of a particular Rotameter can be increased by__________________?**

**A. Use of floats of different densities**

B. No means

C. Decreasing the diameter of the float

D. Increasing the diameter of the float

**The value of critical Reynolds number for pipe flow is_________________?**

**A. 1,300**

B. 100,000

C. 10,000

D. None of these

**The contraction co-efficient for Borda’s mouthpiece (for frictionless fluid) is__________________?**

A. 0.94 **B. 0.5**

C. 0.1

D. 1

**In a stabilised soap bubble, pressure inside it compared to external pressure is________________?**

**A. More**

B. Same

C. Less

D. Unpredictable

**Volute of a centrifugal pump should be designed in a fashion, such that the________________?**

**A. Kinetic head gets converted into static head**

B. Mean velocity remains constant

C. Moving stream gradually reduces velocity

D. None of these

**For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively) ?**

A. B & G coincide **B. B is above G**

C. G is above B

D. None of these

**Which of the following has the maximum compression ratio ?**

A. Compressor

B. Blower **C. Vacuum pump**

D. Fan

**A mixed flow centrifugal pump_______________________?**

**A. Employs such an impeller, through which the flow is a combination of radial & axial flow**

B. Pumps the two fluids separately and then mixes them

C. Mixes the two fluids before pumping them

D. Employs impellers in both the radial & axial directions

**A compressor that takes suction at a pressure below atmospheric and discharge against atmospheric pressure is called a ____________ pump?**

A. Volute

B. Sump **C. Vacuum**

D. Submerged

**Momentum correction factor used in fluid flow problems accounts for the__________________?**

A. Change in direction of flow

B. Change in pressure

C. Change in total energy **D. Non uniform direction of velocities at inlet & outlet sections**

**Isothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the______________?**

A. Reynolds number

B. Wall roughness **C. Both A. & B.**

D. Neither A. nor B.

**Minimum porosity for fluidisation is____________________?**

A. That corresponding to completely fluidised bed

B. That corresponding to static bed **C. The porosity of the bed when true fluidisation begins**

D. Less than that of the’ static bed

**In area meter (e.g., Rotameter), with increase in the fluid flow rate, the___________________?**

A. Area through which fluid flows does not vary **B. Pressure drop is almost constant**

C. Pressure drop increases linearly

D. None of these

**In case of a centrifugal pump, the theoretical head developed is dependent on the _____________ the impeller?**

A. Diameter of

B. Speed of

C. Fluid velocity leaving**D. All A., B. and C.**

#### Fluid Mechanics Mcqs

**Terminal velocity is_____________________?**

**A. A constant velocity with no acceleration**

B. Attained after moving one-half of total distance

C. A fluctuating velocity

D. None of these

**Drag co-efficient for motion of spherical particles in a stationary fluid in the stoke’s law range is_________________?**

**A. 24/NRe,P**

B. 64/NRe,P

C. 16/NRe,P

D. 48/NRe,P

**In power law, δ = [A (du/dy)2 + B] then the fluid is__________________?**

**A. Newtonian**

B. Thixotropic

C. Dilatant

D. Rheopectic

**A bed of spherical particles (specific gravity 2.5) of uniform size 1500 μm is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Ergun’s equation for the above fluid-particle system (in SI units) is given below: Δ P/L = 375 × 103 VOM + 10.94 × 106 V2 OM (SI units) If water is to be used as the fluidising medium, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?**

A. 0.5

B. 0.2 **C. 0.7**

D. 0.8

**A rectangular surface 3′ × 4′, has the lower 3 edge horizontal and 6′ below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force on one side of the surface is (where, y = specific weight of water) ?**

A. 49.2y **B. 48y**

C. 39.6y

D. 58y

**What is the unit of kinematic viscosity in SI unit ?**

**A. M2/sec**

B. Kg. sec/m

C. N/m2. sec

D. None of these

**Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the_______________?**

A. Drag on column walls

B. Drag on particles **C. Bed height**

D. Bed voidage

**The main factor on which the behaviour of a mass of fluidised solid depends mainly is the___________________?**

A. Particle size

B. Fluid characteristics **C. Both A. and B.**

D. Neither A. nor B.

**Curve III in the bellow diagram represents a/an________________?**

A. Ideal plastic **B. Pseudo plastic fluid**

C. Dilatent fluid

D. None of these

**The capacity of a centrifugal pump Can be increased by increasing the_________________?**

A. Number of pumps and joining them in series

B. Impeller diameter or speed

C. Number of pumps and joining them in parallel**D. All A., B. and C.**

**The unit of velocity head is_________________?**

A. ft-lb/ft3

B. ft-lb/sec **C. ft-lbf/lb**

D. ft-lbf/sec

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

A. Make the pipe joint leak-proof

B. Keep the pipe in proper orientation **C. Account for contraction/expansion of pipe due to temperature changes of the surroundings**

D. Account for the pressure variation side the pipeline

**For a given Reynolds number, in a hydraulically smooth pipe, further smoothening ____________ the friction factor?**

**A. Brings about no further reduction of**

B. Decreases

C. Increases

D. None of these

**Horsepower requirement for given pump capacity depends upon the_______________?**

A. Specific gravity of the liquid

B. Discharge head

C. Suction lift **D. All A., B. and C.**

**The buoyant force acting on a floating body is dependent on the _______________?**

A. Depth of immersion of the body **B. Weight of the liquid displaced**

C. Viscosity of the liquid

D. Surface tension of the liquid

**Which of the following is used for pumping crude oil from oil well ?**

A. Gear pump

B. Single stage centrifugal pump

C. Screw pump**D. Duplex/triplex reciprocating pump**

**A stream line is___________________?**

**A. Fixed in space in steady flow**

B. Drawn normal to the velocity vector at every point

C. Always the path of particle

D. A line connecting the mid points of flow cross-section

**Froude number is the ratio of__________________?**

A. Drag stress to shear stress

B. Shear stress to gravitational stress

C. Inertial stress to shear stress**D. Inertial stress to gravitational stress**

**Hydraulic diameter for non-circular ducts is equal to ___________ times the area of flow divided by the perimeter?**

A. Three

B. Two **C. Four**

D. Eight

**Propeller type centrifugal pumps are most suitable for__________________?**

A. Low capacity at high heads **B. High capacity at low heads**

C. High capacity at high heads

D. Low capacity at low heads

**Mach number is defined as the ratio of the local flow velocity to the sonic velocity in the fluid. For what value of Mach number, the gases are considered incompressible ?**

**A. < 0.3**

B. 50

C. > 3

D. 1

**A hydraulic press has a ram of 10 cms in diameter and a plunger of 1 cm in diameter. The force required on the plunger to raise a weight of 10 tons on the ram is _____________ kg?**

A. 1000 **B. 100**

C. 10

D. 10000

**Power number is the ratio of____________________?**

**A. Drag stress to inertial stress**

B. Inertial stress to gravitational stress

C. Inertial stress to drag stress

D. Gravitational stress to drag stress

**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 power consumed now will be _____________ hp?**

**A. 0.5**

B. 4

C. 2

D. 1

**A Newtonian fluid is that__________________?**

A. Which needs a minimum shear, before it starts deforming

B. Which follows Newton’s law of motion **C. For which shear & deformation are related as T = μ (∂u/∂y)**

D. None of these

**Bernoulli’s equation accounts for the_____________________?**

A. Various masses

B. Various momentums **C. Different forms of mechanical energy**

D. None of these

**The line of action of the buoyant force acts through the____________________?**

**A. Centroid of the displaced volume of fluid**

B. Centroid of the volume of any floating body

C. Centre of gravity of a submerged body

D. None of these

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

**A. Kozeny-Carman**

B. Leva’s

C. Blake-Plummer

D. Fanning friction factor

**For an incompressible fluid, the bulk modulus of elasticity is____________________?**

A. 1 N **B. ∞ N/m2**

C. 5 kg/m3

D. 0 N/m

#### Chemical Heat Transfer Mcqs

**Steady non-uniform flow is exemplified by flow through a/an___________________?**

A. Long pipe at decreasing rate

B. Long pipe at constant rate

C. Expanding tube at increasing rate**D. Expanding tube at constant rate**

**The frictional resistance in laminar flow does not depend on the_________________?**

**A. Area of surface in contact**

B. Fluid temperature

C. Flow velocity

D. Pressure of flow

**The momentum correction factor for the velocity distribution of laminar flow is____________________?**

A. 1.66

B. 1.3

C. 2.5**D. None of these**

**_____________________ pumps are a group of vacuum pumps ?**

**A. Hyster**

B. Mono

C. Sump

D. Submerged

**Differential manometer measures the___________________?**

A. Gauge pressure

B. Absolute pressure **C. Pressure difference**

D. Pressure gradient

**With decrease in particle size to be fluidised by a particular fluid, the operating range of fluidisation velocity___________________?**

A. Squeezes

B. Widens **C. Does not change**

D. Unpredictable from the data

**The length of the tube necessary for the boundary layer to reach the centre of the tube and for fully developed flow to be established is called the _____________ length?**

A. Prandtl mixing **B. Transition**

C. Equivalent

D. None of these

**Diaphragm pumps are used to transport_________________?**

A. Liquids

B. Solids

C. Fluids**D. Slurries**

**Rubber latex is an example of ______________ fluid?**

A. Newtonian

B. Dilatants **C. Pseudo plastic**

D. Bingham plastic

**Discharge from a 24 inch pipe of water at 10 ft/sec will be _____________ ft3/sec?**

A. 32.36

B. 7.65

C. 48.22**D. 125.6**

**For the same flow rate of a fluid, the pressure drop is the least for ____________________?**

**A. Venturimeter**

B. Flow-nozzle

C. Orificemeter

D. Δp is same for all

**For laminar flow of Newtonian fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to (where, μ = fluid viscosity ) ?**

A. √μ **B. 1/μ**

C. μ

D. 1/√μ

**Pumping of a corrosive liquid is generally preferred to be done by a ______________ pump, as it can be made of a variety of materials including plastics?**

A. Sump **B. Gear**

C. Positive displacement

D. Piston

**The line traced by a single fluid particle as it moves over a period of time is called ______________ line?**

A. Equipotential **B. Path**

C. Stream

D. None of these

**While starting an axial flow pump, its delivery valve should be kept _______________?**

**A. Open**

B. Either open or closed

C. Closed

D. None of these

**Which of the following is not an advantage of fluidisation from transfer operation point of view ?**

A. Intimate contact of the fluid with all parts of the solid particles**B. Lower fluid pumping power requirement**

C. Prevention of particle segregation

D. Minimisation of temperature variation

**What is the speed of sound (m/sec) in ordinary water ?**

**A. 1500**

B. 1000

C. 330

D. 3000

**Fanning friction factor is equal to (where, fB = Blasius friction factor) ?**

**A. fB/4**

B. 4fB

C. fB/2

D. 2fB

**With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss_______________?**

A. Increases

B. Decreases **C. Remain constant**

D. Increases linearly

**_____________ forces do not act in case of fluid flow ?**

A. Vibratory **B. Tensile**

C. Elastic

D. Centrifugal

**Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss ?**

A. Rotameter **B. Venturimeter**

C. Flow nozzle

D. Orificemeter

**One dimensional flow implies________________________?**

A. Steady uniform flow

B. Flow in a straight line

C. Unsteady uniform flow**D. A flow which does not account for changes in transverse direction**

**Non-colloidal solution is an example of the _______________ fluid?**

A. Dilatent **B. Newtonian**

C. Non-Newtonian

D. Pseudo-plastic