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

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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:

**In a dry packed bed, the pressure drop will be changed by increasing the flow rate as__________________?**

**A. V1.8**

B. V

C. V-0.8

D. V-1

**Toothpaste is a__________________?**

A. Pseudo-plastic

B. Bingham plastic

C. Newtonian liquid**D. Dilatent**

**Drag force on the float of a Rotameter is (where Q = flow rate of the)__________________?**

A. ∝ √Q

B. ∝ Q

C. ∝ Q2**D. Constant**

**A piezometer provided in the pipe measures__________________?**

A. Dynamic pressure **B. Static pressure**

C. Friction factor

D. None of these

**Which of the following equations is valid for laminar flow of a fluid through packed bed ?**

A. Hagen-Poiseuille equation **B. Kozeny – Karman equation**

C. Fanning equation

D. Blake-Plummer equation

**As per Newton’s law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to (where, μ = fluid viscosity) ?**

A. μ2 **B. μ**

C. 1/μ

D. 1/μ2

**Foot valves are provided in the suction line of a centrifugal pump to ____________________?**

**A. Avoid priming, every time we start the pump**

B. Minimise the fluctuation in discharge

C. Remove the contaminant present in the liquid

D. Control the liquid discharge

**What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate ?**

**A. 0.5**

B. 1.5

C. 1

D. 2

**In case of end to end connection of two or more pipes in series, the ______________ each pipe?**

**A. Same rate of flow passes through**

B. Total flow rate is the sum of flow rate in

C. Rate of flow in each pipe is proportional to the length of

D. Head loss is same through

**The energy loss over a length of pipeline according to Darcy-Weisbach equation for pipe flow is _______________ the mean velocity of flow?**

A. Inversely proportional to **B. Directly proportional to square of**

C. Directly proportional to

D. Inversely proportional to square of

**Existence of boundary layer in fluid flow is because of the_________________?**

A. Fluid density

B. Surface tension **C. Fluid viscosity**

D. Gravity forces

**The continuity equation of fluid mechanics utilises the principle of conservation of _________________?**

A. Energy **B. Mass**

C. Momentum

D. Both B. & C.

**The head loss due to sudden contraction is proportional to___________________?**

A. Turbulence **B. Velocity head**

C. Velocity

D. None of these

**Critical velocity in a pipe flow_________________?**

A. Independent of fluid density **B. Increases as pipe diameter increases**

C. Increases as fluid viscosity increases

D. None of these

**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 ?**

A. f1 < f2

B. f1 = f2 **C. f1 > f2**

D. Data not sufficient to relate f1 & f2

**Choose the set of pressure intensities that are equivalent ?**

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

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

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

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

**Velocity head on sudden enlargement in a horizontal pipe is converted into ______________ head?**

A. Elevation**B. Pressure**

C. Both of the above

D. Neither of the above

**Transition length for turbulent flow in smooth pipe is equal to _____________ times the pipe diameter?**

A. 5

B. 0.5 **C. 50**

D. 500

**Stoke’s law is valid, when the particle Reynolds number is ______________________?**

**A. < 1**

B. < 5

C. > 1

D. None of these

**If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is_________________?**

A. Greater in 1 mm dia tube

B. Same in both the tubes **C. Greater in 0.5 mm dia tube**

D. Zero in both the tubes

**The blades of a centrifugal impeller are said to be curved forward, if the ____________ of the motion of impeller blades?**

A. Inlet tip of a blade is towards the direction

B. Outlet tip of a blade curves in a direction opposite to that

C. Inlet tip of a blade curves in a direction opposite to that **D. Outlet tip of a blade is towards the direction**

#### Chemical Heat Transfer Mcqs

**A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is _____________ litres?**

A. 1.1 **B. 660**

C. 600

D. 60

**Plunger pumps are used for__________________?**

**A. Higher pressure**

B. Viscous mass

C. Slurries

D. None of these

**The maximum delivery pressure of a reciprocating compressor may be about ______________ kg/cm2?**

A. 2000

B. 1000

C. 3000**D. 4000**

**Identification of pipelines carrying different liquids and gases is done by the ____________ of the pipe?**

A. Altitude **B. Colour**

C. Diameter

D. None of these

**Which of the following is not a dimension-less parameter ?**

A. Froude number

B. Pressure-co-efficient **C. Kinematic viscosity**

D. Weber number

**Pressure co-efficient is the ratio of pressure forces to __________________________ forces?**

A. Viscous **B. Inertial**

C. Gravity

D. None of these

**Select the correct practical example of steady non-uniform flow?**

A. Motion of river around bridge piers

B. Motion of water around a ship in a lake **C. Steadily decreasing flow through a reducing section**

D. Steadily increasing flow through a pipe

**A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now_________________?**

A. Remain same **B. Decrease**

C. Increase

D. Data insufficient to predict

**Purpose of air lift pump is to____________________?**

A. Lift compressed air

B. Compress air **C. Lift water from a well by using compressed air**

D. Lift air under negative pressure

**Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newton’s law of viscosity. (II) Newton’s second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to boundary. (V) Fluid cannot penetrate a boundary?**

A. I, II, V **B. II, III, V**

C. I, II, III

D. II, IV, V

**For steady ideal fluid flow, the Bernoulli’s equation states that the_________________?**

A. Energy is constant throughout the fluid

B. Velocity is constant along a stream line **C. Energy is constant along a stream line, but may vary across stream lines**

D. None of these

**The velocity for subsonic flow in a pipeline_______________?**

**A. Increases in the downstream direction**

B. Decreases in the downstream direction

C. Is constant

D. Is independent of the area of flow

**Scale up of agitator design requires________________?**

A. Dynamic similarity only

B. Geometrical similarity only

C. Both geometrical and dynamic similarity**D. All geometrical, dynamic and kinematic similarity**

**The percentage slip in a reciprocating pump set is given by the % of (where, Q1 = actual discharge Q2 = theoretical discharge) ?**

A. Q2/Q1

B. Q1/Q2

C. (Q2 – Q1)/Q1**D. (Q2 – Q1)/Q2**

**Glass pipes can be joined by__________________?**

A. Welding

B. Flanges

C. Soldering**D. Bell and spigot joint**

**For the same terminal conditions and fitting size, the least friction loss is incurred in a/an ?**

A. 45° elbow **B. Union**

C. T-joint

D. 90°bend

**At what value of crank angle (roughly), no flow of water from or into the air vessel takes place in case of a double acting reciprocating pump ?**

**A. 40° and 140°**

B. 90° and 80°

C. 45° and 60°

D. 20° and 120°

**The ratio of maximum to average velocity in case of streamline flow between parallel plates is______________________?**

A. 2 **B. 1.5**

C. 1

D. 2.5

**The valve commonly used in pipes larger than 2″ dia is a______________?**

A. Plug-cock

B. Globe valve **C. Gate valve**

D. Check valve

**The energy loss in flow through Venturimeter is less than that through flow nozzle, because in case of a flow nozzle, the ?**

A. Throat diameter is more

B. Length is shorter **C. Sudden expansion of flow in the downstream occurs**

D. Distance between the throat and the inlet is more

**Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?**

A. Hagen-Poiseuille equation **B. Blake-Plummer equation**

C. Fanning equation

D. Kozeny-Carman equation

**Which of the following flow measuring devices is an area meter ?**

A. Orificemeter

B. Venturimeter

C. Anemometer**D. Rotameter**

**Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(ε/D) + (1.26/NRe √F). It reduces to Nikuradse equation for a value of (ϵ/D) equal to __________________?**

A. ∞ **B. 1**

C. 0

D. 0.5

**Potential function is applicable only for __________ flow?**

**A. Irrotational**

B. Steady

C. Turbulent

D. None of these

**The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids ?**

A. Moving at low velocities

B. Having high viscosities **C. Both A. & B.**

D. Neither A. nor B.

**The losses in open channel flow generally vary as the ________________?**

A. Square of the velocity **B. First power of the roughness**

C. Inverse of the roughness

D. Inverse square of hydraulic radius

#### Fluid Mechanics Mcqs

**Flow rate of high velocity flue gas discharged through a stack to the atmosphere can be most conveniently measured by a _________________?**

**A. Pitot tube**

B. Rotameter

C. Manometer

D. None of these

**The actual velocity at vena-contracta for flow through an orifice from a reservoir is given by_____________________?**

**A. Cv . √(2gH)**

B. Cd . √(2gH)

C. Cc . √(2gH)

D. Cv . Va

**The component of acceleration resulting due to unsteady nature of flow is called ____________ acceleration?**

A. Convective **B. Local**

C. Normal

D. Tangential

**In hindered settling, the particles are_________________________?**

A. Not affected by other particles and the wall

B. Placed farther from the wall **C. Near each other**

D. None of these

**The Prandtl mixing length is_________________?**

A. Independent of the shear stress

B. Independent of radial distance from the pipe axis

C. Zero at the pipe wall and is a universal constant **D. Useful for computing laminar flow problems**

**The ratio of actual discharge to theoretical discharge through an orifice is equal to______________?**

**A. Cc . Cv**

B. Cv . Cd

C. Cc . Cd

D. Cd/Cv

**The distribution of shear stress in a stream of fluid in a circular tube is_____________________?**

A. Linear with radius for laminar flow only

B. Linear with radius for turbulent flow only **C. Linear with radius for both laminar & turbulent flow**

D. Parabolic with radius for both laminar & turbulent flow

**Which of the following is dimensionless ?**

A. Specific volume **B. Fanning friction factor**

C. Angular velocity

D. None of these

**A floating/submerged body is always stable, if its centre of gravity___________________?**

A. And centre of buoyancy coincide

B. Lies above its centre of buoyancy **C. Lies below its centre of buoyancy**

D. Lies above its metacentre

**Boundary layer separation is caused by the ____________________?**

A. Reduction of pressure below vapour pressure

B. Reduction of boundary layer thickness to zero **C. Adverse pressure gradient**

D. Reduction of pressure gradient to zero

**Which of the following conditions must be satisfied for lift force to be developed ?**

A. The body should be stream lined

B. The body should be bluff body **C. Circulation around the body is essentially required**

D. The main stream velocity must approach the velocity of sound in that fluid medium

**Correction for capillary effect in manometers (used for pressure measurement) need not be applied, if diameter of the manometer tube is _____________ mm?**

A. < 10 **C. > 12.5**

D. 4

**Diaphragm valves are used for handling _______________ fluids?**

**A. Corrosive**

B. Non-Newtonian

C. Viscous

D. Solid suspended

**Vane anemometer __________________?**

A. Is a variable head meter

B. Is an area meter **C. Rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed**

D. None of these

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

**A. Newtonian**

B. Pseudo-plastic

C. Dilatant

D. Non-Newtonian

**The time of oscillation of a floating body is _________________?**

A. Independent of the Metacentric height

B. Longer, if Metacentric height is increased

C. Dependent on the buoyant forces only**D. None of these**

**For turbulent fluid flow in pipe, the expression for Prandtl one seventh power law is (where, r = pipe radius, x = distance) ?**

**A. V/Vmax = (x/r)1/7**

B. V/Vmax = (x.r)1/7

C. V/Vmax = (r/x)1/7

D. None of these

**The Reynolds number for an ideal fluid flow is _________________?**

A. 4000

B. 2100-4000

C. 4 **D. ∞**

**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, then the new head will be ______________ metres?**

**A. 2**

B. 8

C. 4

D. 5.5

**Enamels and paints are generally _______________ fluid?**

A. Thixotropic **B. Pseudo-plastic**

C. Rheopectic

D. Dilatant

**The distance between metacentre and ______________ is called metacentric height?**

A. Centre of buoyancy **B. Centre of gravity**

C. Water surface

D. None of these

**______________ is an example of axial flow impeller?**

A. Turbine

B. Paddle **C. Propeller**

D. All A., B. and C.

**An ideal fluid is___________________?**

**A. Frictionless & incompressible**

B. Highly viscous

C. One, which obeys Newton’s law of viscosity

D. None of these

**A weir is used to measure the large water discharge rate from a river or from an open channel. A weir is not of _______________ shape?**

**A. Circular**

B. Triangular

C. Rectangular

D. Trapezoidal

**Centrifugal pump can’t be used to pump _____________________?**

A. Moderately viscous vegetable oil used in soap industry

B. Molten sodium (used as a coolant in Fast Breeder Reactor) **C. Thick molten soap at 80°C**

D. None of the above

**____________ flow means the flow of incompressible fluid with no shear ?**

**A. Potential**

B. Creep

C. Streamline

D. Boundary layer

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

**A. √d**

B. d2

C. d1/3

D. d2/3

**Normal depth in open channel flow is the depth of flow in the channel ____________________?**

**A. Corresponding to uniform flow**

B. Corresponding to steady flow

C. Measured normal to the channel bed

D. None of these

**Ratio of inertial forces to surface tension forces is called the _____________ number?**

A. Froude

B. Euler

C. Mach**D. Weber**

**Two piping system are said to be equivalent, when the ______________ are same?**

**A. Fluid flow rate & friction loss**

B. Diameter & friction factor

C. Length & friction factor

D. Length & diameter

**In which of the following cases, it is possible for flow to occur from low pressure to high pressure ?**

A. Flow of air downward in a pipe **B. Flow through a converging section**

C. Flow of liquid upward in a vertical pipe

D. Impossible in a constant cross-section conduit

**An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonian fluid beyond yield stress. Which of the following is an ideal plastic ?**

**A. Sewage sludge**

B. Blood

C. Rubber latex

D. Sugar solution

#### Chemical Engineering Basics Mcqs

**In an incompressible flow of fluid, the fluid ________________?**

A. Compressibility is greater than zero

B. Temperature remains constant **C. Density does not change with pressure & temperature**

D. Is frictionless

**A Venturimeter measures the___________________?**

A. Pressure

B. Velocity head

C. Point velocity**D. None of these**

**The discharge through a rectangular weir varies as ___________________?**

A. H5/2

B. H1/2

C. H2/5**D. H3/2**

**To handle smaller quantity of fluid at higher discharge pressure, use a ______________ pump?**

**A. Reciprocating**

B. Volute

C. Centrifugal

D. Rotary vacuum

**Froude number is not a factor__________________?**

A. For unbaffled tank **B. When there is no vortex formation**

C. For Reynolds number greater than 300

D. None of these

**Check valve is used for ________________ flow?**

A. Multidirectional **B. Unidirectional**

C. Very precise control of

D. None of these

**In turbulent flow, the__________________?**

A. Momentum transfer is on molecular scale only

B. Fluid particles move in an orderly manner

C. Shear stress is caused more effectively by cohesion than momentum transfer**D. Shear stresses are generally larger than in a similar laminar flow**

**Bernoulli’s equation for steady, frictionless, continuous flow states that the ______________ at all sections is same?**

A. Velocity head **B. Total energy**

C. Total pressure

D. None of these

**A streamline is a line in flow field _________________?**

A. Along which a fluid particle travels

B. That is traced by all the fluid particles passing through a given point **C. Such that at every point on it, the velocity is tangential to it**

D. None of these

**The co-efficient of discharge of an orificemeter is a function of ________________?**

A. Ratio of orifice dia to pipe dia

B. Reynolds number at the orifice **C. Both A. and B.**

D. None of the above parameters, and has a constant value of 0.61

**A 2″ gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was Δp. For the same discharge, the pressure drop across globe valve is__________________?**

A. < Δp

B. Δp **C. > Δp**

D. Δp2

**A centrifugal pump designed to pump water is employed to pump a more viscous oil. In the later case, the pump_________________?**

A. Capacity is reduced

B. Develops a lower head

C. Requires more power**D. All A., B. and C.**

**The pressure and power requirement of a gas fan at constant speed & capacity varies ____________ the gas density?**

**A. Directly as**

B. Inversely as

C. Inversely as square root of

D. As square of

**The maximum depth from which a centrifugal pump can draw water is________________?**

A. Dependent on the power of the pump

B. Dependent on the speed of the pump **C. 34 feet**

D. 150 feet

**Laminar flow is characterised by the nonexistence of_________________?**

A. Eddies

B. Pressure fluctuation

C. Deviating velocities**D. All A., B. & C.**

**The capillary rise of mercury is maximum in glass tube of dia _____________ mm?**

**A. 0.5**

B. 2

C. 1

D. 5

**Boundary layer exists in flow_________________?**

**A. Of real fluids**

B. In pipes only

C. Over flat surfaces only

D. Of ideal fluids only

**The most serious disadvantage of an orificemeter is that________________?**

A. It is very costly

B. It is not very accurate **C. Most of the pressure drop is not recoverable**

D. It is not suitable for measuring gas flow

**Drag is the force component exerted on an immersed object, ?**

A. The component being normal to the flow direction **B. The component being parallel to the flow direction**

C. Passing the centroid of the body at 60°to the direction of motion

D. None of these

**Paper pulp is an example of _____________ fluid?**

A. Newtonian **B. Bingham plastic**

C. Dilatant

D. Pseudo-plastic

**The vent valve provided in a liquid handling centrifugal pump is___________________?**

A. Helpful in easy removal of samples

B. Used to release any gases that might be vapour locking the pump

C. Generally a needle valve **D. All A., B. and C.**