#### 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:

**The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the_________________?**

A. Suction

B. Discharge **C. Suction minus vapor pressure of the liquid at suction temperature**

D. Discharge minus vapor pressure of the liquid at the discharge temperature

**Nominal size of the discharge pipe of a pump is usually _____________ the nominal size of the inlet pipe?**

**A. Smaller than**

B. Same as

C. Larger than

D. Twice

**Which of the following has the minimum compressibility ?**

**A. Water at room temperature**

B. Oxygen at room temperature

C. Air at room temperature

D. Nitrogen at room temperature

**Power loss in an orificemeter is _____________ that in a Venturimeter?**

A. Same as

B. Less than **C. More than**

D. Data insufficient, cannot be predicted

**The unit of dynamic viscosity in SI unit is__________________?**

**A. kg/m. sec**

B. m2 /sec

C. N/m2

D. m/N. sec

**The pitot static tube does not measure the _____________ pressure?**

A. Total

B. Static

C. Difference in static & dynamic**D. All A., B. and C.**

**Vena-contracta formed during flow of a liquid through an orificemeter has__________________?**

**A. Minimum liquid cross-section**

B. Minimum velocity of fluid stream

C. More diameter compared to orifice diameter

D. None of these

**For Laminar flow through a packed bed, the pressure drop is proportional to (Vs is the superficial liquid velocity and Dp is the particle diameter) ?**

**A. Vs/Dp2**

B. Vs2/Dp3

C. Vs2/Dp2

D. Vs/Dp3

**What is the co-efficient of contraction, if a fluid jet discharging from a 50 mm diameter orifice has a 40 mm diameter at its vena-contracta ?**

**A. 0.64**

B. 0.32

C. 1.65

D. 0.94

**All pipes of a particular nominal size have the same_________________?**

A. Thickness **B. Outside diameter**

C. Inside diameter

D. None of these

**Purpose of hydraulic accumulator is to_______________?**

A. Ensure intermittent supply of hydraulic pressure

B. Accumulate pressure to increase force

C. Increase the pressure and store/ accumulate it **D. Generate high pressure to operate hydraulic machines like cranes, lifts, presses etc**

**Dimension of absolute viscosity is_________________?**

**A. ML-1T-1**

B. ML-1T

C. MLT-1

D. MLT

**The Prandtl Pitot tube measures the__________________?**

**A. Velocity at a point in the flow**

B. Average flow velocity

C. Pressure at a point

D. Pressure difference in pipe flow

**A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, η0 = 10 KPa, is shared between flat parallel plates separated by a distance of 10-3 m. The top plate is moving with a velocity of 1 m/s. The shear stress on the plate is________________?**

A. 30 KPa **B. 20 KPa**

C. 10 KPa

D. 40 KPa

**The equation f-0.5 = 4.07 loge (NRe √f)-0.6 is called the ____________?**

A. Fanning equation **B. Von-Karman equation**

C. Colebrook formula

D. None of these

**Laminar flow of a Newtonian fluid ceases to exist, when the Reynolds number exceeds___________________?**

A. 1500 **B. 2100**

C. 4000

D. 3000

**For an unstable equilibrium of a floating body (where, M = metacentre.) ?**

A. M & G coincide **B. M is below G**

C. M is above G

D. None of these

**Schedule number of a pipe, which is a measure of its wall thickness, is given by ________________?**

**A. 1000 P’/S**

B. 1000 S/P

C. 100 P’/S

D. 10000 P’/S

#### Nuclear Power Engineering Mcqs

**Steady fluid flow occurs, when the derivative of flow variables satisfy the following condition.**

A. ∂/∂s = constant **B. ∂/∂t = 0**

C. ∂/∂s = 0

D. ∂/∂t = constant

**When the momentum of one fluid is used for moving another fluid, such a device is called a/an______________?**

**A. Jet pump**

B. Acid egg

C. Blower

D. None of these

**The velocity profile for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is__________________?**

A. Flat

B. Parabolic

C. Flat near the wall and parabolic in the middle**D. Parabolic near the wall and flat in the middle**

**In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of___________________?**

A. Absolute roughness

B. Relative roughness **C. Friction co-efficient for flows at equal Reynold number**

D. All A., B. & C.

**At a constant speed of the centrifugal pump, it‟s _____________ the impeller diameter?**

A. Head varies as the square of

B. Capacity varies directly with

C. Horsepower varies as the cube of**D. All A., B. and C.**

**Foot valves provided in pumps are ____________ valves?**

A. Three/four way

B. Relief

C. Pressure reducing**D. Directional control**

**Which of the following can be used for the direct measurement of volumetric flow rate of slurry ?**

A. Orificemeter

B. Venturimeter **C. Rotameter**

D. Pitot tube

**The dimension of dynamic viscosity is__________________?**

**A. ML-1T-1**

B. LT-2

C. L2T-1

D. ML-1T-2

**In case of centrifugal fan or blower, the gas capacity varies as __________________?**

**A. Speed**

B. (Speed)3

C. (Speed)2

D. (Speed)0.5

**The maximum delivery pressure of compressors can be upto _____________ atmospheres?**

A. 10

B. 250

C. 100 **D. 1000**

**Dean number is concerned with the____________________?**

A. Psychrometry **B. Fluid flow through helical pipes**

C. Power consumption in agitated vessels

D. Fluid-particle interaction

**A pipe is defined as ‘hydraulically smooth’, if the friction factor_________________?**

A. Is zero irrespective of the Reynolds number **B. For a given Reynolds number remains constant even on further smoothening of the pipe**

C. Is not a function of Reynolds number

D. None of these

**The normal stress is the same in all directions at a point in a fluid, when the fluid is__________________?**

A. Incompressible

B. Non-viscous

C. Both A. and B.**D. Having no motion of one fluid layer relative to the other**

**In case of a ____________ the energy of flow is considerably decreased downstream of the machine?**

A. Centrifugal pump **B. Turbine**

C. Blower

D. Centrifugal fan

**Acceleration head in a reciprocating pump_______________________?**

A. Decreases the work done during suction stroke

B. Increases the work done during delivery stroke **C. Does not change the work requirement of the pump**

D. Increases the work done during suction stroke

**With increase in the ratio of orifice diameter to pipe diameter, the fraction of the orifice pressure differential that is permanently lost________________?**

A. Remains unchanged **B. Decreases**

C. Increases

D. Increases exponentially

**In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature) ?**

A. 1/T

B. 1/√T **C. √T**

D. T

**One horsepower is equal to________________?**

**A. 550 lbf.ft/second**

B. 550 lbf.ft./hr

C. Both A. and B.

D. 550 kgf.m/second

**An ideal nozzle design aims at________________?**

A. Suppressing boundary layer separation

B. Minimising wall friction **C. Both A. & B.**

D. Neither A. nor B.

**In the laminar boundary layer flow over a flat plate, the ratio (δ/x) varies as: (where, ‘δ’ is the boundary layer thickness and ‘x’ is the distance from the leading edge in the direction of flow)?**

A. Re

B. 1/Re

C. √Re **D. Re-1/2**

**In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where M = molecular weight of the gas) ?**

**A. 1/√M**

B. 1/M

C. √M

D. M

**The bulk modulus of elasticity of a liquid__________________?**

A. Decreases with pressure

B. Is zero for incompressible liquid

C. Is independent of temperature & pressure**D. Increases with pressure**

**The most suitable flow measuring device for the fluid flow measurement in a very large diameter pipeline is a____________________?**

A. Kennison nozzle **B. Pitot tube**

C. Weir

D. V-notch

**The terminal velocity of a solid spherical particle falling through a stationary fluid mass in the Stoke’s law range is proportional to the_____________________?**

A. Square of particle size

B. Inverse of fluid viscosity

C. Difference in the densities of the particle & fluid**D. All A., B. and C.**

**The resistance wire used in a hot wire anemometer for conducting electrical current is made of__________________?**

A. Chromium **B. Tungsten**

C. Copper

D. Aluminium

**As the velocity V and thus the Reynolds number of a flow past a sphere increases from very low value, the drag force for Re << 1 ?**

**A. Increases linearly with V**

B. Decreases as V2

C. Decreases linearly with V

D. None of these

**The centre of pressure is_________________?**

A. Always above the centroid of the area

B. Always below the centroid of the area **C. A point on the line of action of the resultant force**

D. At the centroid of the submerged area

**The rate of shear versus the shear stress curves are time dependent for _____________ fluid?**

A. Rheopectic

B. Thixotropic **C. Both A. & B.**

D. Neither A. nor B.

**The flow of a liquid through tapering pipe at a constant rate is an example of _______________ flow?**

A. Unsteady uniform **B. Steady non uniform**

C. Steady uniform

D. Unsteady non uniform

**Very small pressure difference (< 5 mm water column) can be most conveniently measured by a/an _____________ manometer?**

A. U-tube mercury

B. U-tube water

C. Inclined tube mercury**D. Inclined tube water**

**In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the _____________ efficiency?**

**A. Manometric**

B. Volumetric

C. Mechanical

D. Overall

**A fluid whose apparent viscosity increases with shear rate is termed as the _____________ fluid?**

A. Viscous

B. Newtonian **C. Dilatant**

D. Non-viscous

**Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = discharge co-efficient, Cc = co-efficient of contraction = (area of jet at vena-contracta/area of opening), Cv = co-efficient of velocity = (actual velocity at vena-contracta/theoretical velocity)?**

A. Cd = Cv/ Cc **B. Cd = Cc.Cv**

C. Cd = Cc/Cv

D. None of these

#### Materials And Construction Mcqs

**A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the average velocity of water flowing through the main pipe is 5 m/sec, the average velocity through the bifurcated pipes is__________________?**

A. 5 √2 m/sec **B. 10 m/sec**

C. 20 m/sec

D. 5 m/sec

**Pick out the Hagen-Poiseuille‟s equation ?**

A. Δp/ρ = 4f (L/D) (V2/2gc)**B. Δp = 32 (μLV/gc. D2)**

C. Δp/L = 1.75 [(1 – ε)/ε3]. (ρV02/gcDp)

D. Δp/L = 150 [(1 – ε)/ε3]. (μ.V02/g2cD)

**The pressure head of a flow meter remains constant for_________________?**

A. Orificemeter

B. Venturimeter **C. Rotameter**

D. Pitot tube

**Which of the following quantities are computed by using the hydraulic radius for noncircular ducts ?**

A. Head loss and velocity

B. Velocity and relative roughness **C. Reynold number, relative roughness and head loss**

D. Reynolds number and friction factor

**A pressure head of 320 metres of water in meters of CCl4 (sp.gr = 1.6) will be__________________?**

A. 320 **B. 200**

C. 100

D. 160

**For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter) ?**

A. 1/D2

B. 1/D **C. 1/D5**

D. D2

**Check in a centrifugal pump is________________?**

A. Generally a globe valve

B. Provided in the discharge line

C. Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running**D. All A., B. and C.**

**Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have_____________?**

A. Smaller discharge

B. Very low speeds **C. Higher capital &maintenance cost**

D. High vibrations

**In an incompressible fluid, the density is____________________?**

A. Greatly affected only by moderate changes in temperature

B. Greatly affected by moderate changes in pressure **C. Not affected with moderate change in temperature & pressure**

D. Sensible to changes in both temperature & pressure

**Turbulent flow generally occurs for cases involving__________________?**

A. Very narrow passages

B. Highly viscous fluid

C. Very slow motion**D. None of these**

**The ratio of wall drag to total drag in the Stoke’s law range is_________________?**

A. 1/3

B. 1

C. 0.5 **D. 2/3**

**For a given Reynold number as d/D for an orifice increases, Cd will (where, d & D are orifice & pipe diameters respectively)?**

**A. Increase**

B. Decrease

C. Remain constant

D. Either A. or B.;

**Speed of sound in an ideal gas depends on its________________?**

**A. Temperature**

B. Specific volume

C. Pressure

D. None of these

**Pipes having diameter 14 inches or more are designated by their_________________?**

**A. Outside diameter**

B. Schedule number

C. Inside diameter

D. None of these

**The temperature in isentropic flow_______________?**

A. Cannot drop and then increase again downstream **B. Depends on Mach number only**

C. Does not depend on Mach number

D. None of these

**Check valves are used_______________?**

A. In bends

B. At high pressure

C. For controlling water flow**D. For unidirectional flow**

**A double acting reciprocating pump compared to a single acting pump (of almost same size working under same pressure levels) would give almost double___________________?**

A. Efficiency **B. Discharge**

C. Head

D. None of these

**Boundary layer separation is caused by the_________________?**

A. Adverse pressure gradient

B. Boundary layer thickness reducing to zero

C. Reduction of pressure to vapour pressure **D. Reduction of pressure gradient to zero**

**If ‘x’ is the depth of flow in an open channel of large width, then the hydraulic radius is equal to________________?**

**A. x**

B. x/3

C. x/2

D. 2x/3

**A differential pressure cell is used for____________________________?**

A. Measuring small pressure difference in liquids

B. Measuring small pressure difference in gases **C. Remote recording of pressure difference**

D. Measuring the difference of the impact & the static pressure

**Which of the following pipe bends will incur the largest head loss ?**

**A. U-bend**

B. 45° bend

C. 30° bend

D. 90° bend

**Which of the fluid forces are not considered in the Reynold’s equation of flow ?**

A. Turbulent forces

B. Viscous forces

C. Pressure forces**D. Compressibility forces**

**Bernoulli‟s equation does not apply to the functioning of a/an__________________?**

A. Venturimeter

B. pitot tube

C. Orificemeter **D. None of these**

**Rotary vacuum pumps can reduce the absolute pressure to as low as __________ mm Hg ?**

A. 0.1

B. 1 **C. 0.01**

D. 0.001

**In fluid flow, the boundary layer separation cannot occur___________________?**

A. In laminar flow

B. At points of abrupt changes in the flow directions

C. In case of boundaries experiencing form drag **D. None of these**

#### Fluid Mechanics Mcqs

**If more than two branches of pipes are to be connected at the same point, then use a/an_________________?**

A. Union

B. Elbow **C. Tee**

D. None of these

**Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve. The extent of pressure thus produced due to water hammer depends on the___________________?**

A. Fluid velocity in the pipe

B. Pipe length

C. Time taken to close the valve**D. All A., B. and C.**

**A mono pump is a __________ pump ?**

A. Piston

B. Centrifugal **C. Positive acting rotary**

D. A group of vacuum

**For pipes that must be broken at intervals for maintenance, the connector used should be a/an__________________?**

**A. Union**

B. Reducer

C. Tee

D. Elbow

**The terminal velocity of a small sphere settling in a viscous fluid varies as the___________________?**

A. Inverse square of the diameter **B. Inverse of the fluid viscosity**

C. First power of its diameter

D. Square of the difference in specific weights of solid & fluid

**A Rotameter through which air at room temperature and atmospheric pressure is flowing gives a certain reading for a flow rate of 100 cc/sec. If helium (molecular weight 4) is used and Rotameter shows the same reading, the flow rate (cc/sec) is__________________?**

A. 42

B. 26 **C. 269**

D. 325

**Co-efficient of velocity is ___________________ the coefficient of discharge?**

A. Equal to **B. More than**

C. Less than

D. Not related to

**The inherent characteristic of an equal percentage valve relating flow rate ‘q’ with valve stem movement ‘x’ are described by the equation_________________?**

**A. dq/dx = K**

B. dq/dx = K/q

C. dq/dx = K.q

D. dq/dx = Kq2

**The terminal velocity of a particle moving through a fluid varies as dp n. What is the value of n’ for Newton’s law regime ?**

**A. 0.5**

B. 1.5

C. 1

D. 3

**Fluidised beds are formed, when the__________________?**

A. Pressure forces equal gravity forces **B. Gravity force is less than the fluid friction**

C. Fluid friction is zero

D. Sum of the fluid friction and pressure forces is equal and opposite to gravity forces

**Which of the following is not concerned with the fluid-particle interaction ?**

A. Froude number

B. Drag co-efficient

C. Galileo number**D. Weber number**

**The ____________ is measured by a piezometric opening?**

A. Static pressure

B. Dynamic pressure **C. Total pressure**

D. Point velocity

**What is the normal range of exit cone angle of a Venturimeter ?**

A. 15 to 25 **B. 7 to 15**

C. 2 to 5

D. >25

**For one dimensional flow of an incompressible fluid in unsteady state in x-direction, the continuity equation is given by_______________?**

**A. ∂u/∂x = 0**

B. ∂ρ/∂t = 0

C. (∂u/∂x) = – (∂ρ/∂t)

D. ∂(ρu)/∂x = 0

**Absolute viscosity of a fluid is a function of the __________ of the fluid?**

A. Motion

B. Shearing stress

C. Pressure & temperature **D. Both B. & C.**

**A pitched-blade turbine draws ______________ a straight blade turbine?**

**A. Less power than**

B. Same power as

C. More power than

D. Data insufficient to predict

**A fluid is pumped at the rate of 10 lb/sec to a height of 55 ft. The horse power required is _____________ hp?**

**A. 1**

B. 5.5

C. 10/55

D. 1/55

**In turbulent flow, a rough pipe has the same friction factor as a smooth pipe____________________?**

A. Everywhere in the transition zone **B. When the roughness projections are much smaller than the thickness of the laminar film**

C. In the zone of complete turbulence

D. When the friction factor is independent of the Reynold’s number

**What is the pipe called which lifts water from a reservoir to a greater height than the initial level in the supply reservoir ?**

A. Tunnel **B. Siphon**

C. Penstock

D. Pressure pipeline

**Which of the following assumptions enables the Euler’s equation of motion to be integrated ?**

**A. The fluid is incompressible**

B. The continuity equation is satisfied

C. The fluid is non-viscous

D. The flow is rotational and incompressible

**Fluid flow at increasing rate through a diverging pipe is an example of ______________ flow?**

A. Non-steady uniform

B. Steady uniform

C. Steady non-uniform**D. Non-steady non-uniform**

**Pascal’s law is valid, only when the fluid is_____________________?**

A. At rest and when the frictionless fluid is in motion **B. At rest**

C. Frictionless and at rest

D. None of these

**Theoretical head developed by a centrifugal pump does not depend upon the _____________ the impeller?**

A. Speed of

B. Radius of

C. Fluid velocity leaving**D. None of these**

**The dimension of kinematic viscosity is_________________?**

A. ML-2T-2 **B. L2T-1**

C. ML-2T-1

D. None of these