Fluid Mechanics For Chemical MCQs

Option A: Surface tension of a liquid is because of the difference in magnitude of adhesive & cohesive

Option B: A hydrometer used for the determination of specific gravities of liquids works on the principle

Option C: In case of unsteady fluid flow, the velocity at any given point does not change with time

Option D: Turbulent fluid flow is characterised by the rapid fluctuation of instantaneous pressure &

Correct Answer: In case of unsteady fluid flow, the velocity at any given point does not change with time ✔

Option A: A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocity

Option B: Newton’s law of viscosity is not applicable to the turbulent flow of fluid with linear velocity

Option C: Laminar flow of viscous liquids is involved in the lubrication of various types of bearings

Option D: Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes

Correct Answer: B. Newton’s law of viscosity is not applicable to the turbulent flow of fluid with linear velocity
distribution ✔

Option A: The eddy viscosity is a function of the type of turbulence involved

Option B: The eddy viscosity is a fluid property

Option C: The viscosity of gas increases with increase in temperature

Option D: The viscosity of a liquid increases with decrease in temperature

Correct Answer: The eddy viscosity is a fluid property ✔

Option A: A Venturimeter with a fixed pressure drop discharges more, when the flow is vertically

Option B: The co-efficient of contraction of a Venturimeter is always unity

Option C: For a fixed pressure drop, the discharge of a gas through a Venturimeter is greater, when

Option D: None of these

Correct Answer: None of these ✔

Option A: Human blood is a Newtonian fluid

Option B: A Newtonian fluid obeys Newton’s law of cooling

Option C: For a non-Newtonian fluid, a straight line passes through the origin in a plot between shear

Option D: Thin lubricating oil is an example of a non-Newtonian fluid

Correct Answer: B. A Newtonian fluid obeys Newton’s law of cooling ✔

Option A: It is always parallel to the main direction of the fluid flow

Option B: It is a line across which there is no flow and it is equivalent to a rigid boundary

Option C: Streamlines intersect at isolated point of zero velocity and infinite velocity

Option D: The fluid lying between any two streamlines can be considered to be in isolation and the

Correct Answer: It is always parallel to the main direction of the fluid flow ✔

Option A: The form drag is dependent upon the occurrence of a wake

Option B: The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance

Option C: An ideal fluid is the one, which has negligible surface tension and obeys the Newton’s law of viscosity

Option D: Existence of the boundary layer in fluid flow is because of viscosity of the fluid.

Correct Answer: C. An ideal fluid is the one, which has negligible surface tension and obeys the Newton’s law of viscosity ✔

Option A: Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer

Option B: Blowers develop a maximum pressure of 2 atmospheres

Option C: Friction losses in pipe fittings are generally expressed in terms of velocity heads

Option D: Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative

Correct Answer: Friction losses in pipe fittings are generally expressed in terms of velocity heads ✔

Option A: For frictionless flow, the fluid pressure entering the venturi meter will be exactly equal to that

Option B: Discharge of fluid through a Venturimeter depends upon the gage difference irrespective of

Option C: Venturimeter occupies less space than an orificemeter

Option D: Venturimeter incurs less power loss compared to an equivalent orificemeter

Correct Answer: Venturimeter occupies less space than an orificemeter ✔

Option A: The discharge through a Venturimeter depends upon Δp only and is independent of

Option B: A Venturimeter with a given gage difference discharges at a greater rate, when the flow is

Option C: For a given pressure difference, the discharge of gas is greater through a Venturimeter, when

Option D: The overall pressure loss is the same in a given pipe line, whether a Venturimeter or a nozzle

Correct Answer: A. The discharge through a Venturimeter depends upon Δp only and is independent of
orientation of the meter ✔

Option A: Momentum transfer in laminar flow results from velocity gradient

Option B: A fluid in equilibrium is not free from shear stress

Option C: The viscosity of a non-Newtonian fluid is a function of temperature only

Option D: Both B. and C.

Correct Answer: D. Both B. and C. ✔

Option A: A forced vortex occurs when fluid rotates as a solid about an axis

Option B: In laminar flow, Newton’s law of viscosity does not apply

Option C: A free vortex occurs, when fluid rotates as a solid

Option D: In turbulent flow, there are neither cross-currents nor eddies

Correct Answer: A forced vortex occurs when fluid rotates as a solid about an axis ✔

Option A: In a static mass of liquid, the pressure at a point is the same for all liquids

Option B: Pressure decreases exponentially with elevation in an isothermal atmosphere

Option C: Atmospheric pressure = absolute pressure ‒ gage pressure

Option D: As per Pascal’s law, the pressure at a point in a static or uniformly moving fluid is equal in all

Correct Answer: In a static mass of liquid, the pressure at a point is the same for all liquids ✔

Option A: The value of Mach number is always unity at the throat

Option B: No shock wave develops in the tube when the Mach number at exit is greater than unity

Option C: Throughout the converging portion of the tube, the density increases in the downstream

Option D: None of these

Correct Answer: No shock wave develops in the tube when the Mach number at exit is greater than unity ✔

Option A: The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonian fluids is (D/4L). Δp

Option B: In the equation, T. gc = k. (du/dy)n the value of ‘n’ for pseudoplastic and Dilatant fluid are 1 respectively

Option C: Shear stress for Newtonian fluid is proportional to the rate of shear in the direction perpendicular to motion

Option D: With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids

Correct Answer: With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids ✔

Option A: The vacuum pressure is always the negative gauge pressure

Option B: The pressure of the liquid measured by a piezometer tube is the gauge pressure

Option C: Manometric liquid should have high surface tension

Option D: The point at which the resultant pressure on an immersed surface acts, is known as the centre

Correct Answer: D. The point at which the resultant pressure on an immersed surface acts, is known as the centre
of gravity ✔

Option A: Fanning friction factor is inversely proportional to Reynolds number always

Option B: The property of a randomly packed bed (with raschig rings) is given by the ratio of the total

Option C: Mach number in an incompressible fluid is always unity

Option D: Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under

Correct Answer: D. Mach number is given by the ratio of the speed of the fluid to that of sound in the fluid under
conditions of flow ✔

Option A: Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation

Option B: Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in

Option C: Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines

Option D: Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine

Correct Answer: D. Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine
blades ✔

Option A: Fluid flow control is required

Option B: Fluid contains dispersed solid particles

Option C: Valve is required to be either fully open or fully closed

Option D: One way flow is required

Correct Answer: Fluid flow control is required ✔

Option A: m

Option B: n

Option C: n-m

Option D: n/m

Correct Answer: m ✔

Option A: Ejector

Option B: Blower

Option C: Injector

Option D: Airlift

Correct Answer: Airlift ✔

Option A: √(HW/π)

Option B: HW/2 (H + W)2

Option C: HW/4 (H + W)2

Option D: 2HW/(H + W)

Correct Answer: HW/2 (H + W)2 ✔

Option A: 1

Option B: 10

Option C: 30

Option D: 50

Correct Answer: 1 ✔

Option A: 2100

Option B: 100

Option C: 0

Option D: ∞

Correct Answer: ∞ ✔

Option A: kg/hr

Option B: kg/m2. hr

Option C: kg/m2

Option D: kg/m3. hr

Correct Answer: kg/m2. hr ✔

Option A: Increased, as it rises to a higher altitude

Option B: Due to the weight of the atmospheric air, that it displaces

Option C: Not dependent on the temperature of the atmosphere

Option D: None of these

Correct Answer: Due to the weight of the atmospheric air, that it displaces ✔

Option A: Butterfly valve

Option B: Globe valve

Option C: Needle valve

Option D: None of these

Correct Answer: Butterfly valve ✔

Option A: 4x

Option B: 2x

Option C: x

Option D: √x

Correct Answer: x ✔

Option A: Particle size

Option B: Fluid viscosity

Option C: Density of both the particle & the fluid

Option D: All A., B. and C.

Correct Answer: D. All A., B. and C. ✔

Option A: The velocity of sound

Option B: Dependent on its cross-sectional area

Option C: Dependent on fluid viscosity

Option D: Dependent on fluid density

Correct Answer: The velocity of sound ✔

Option A: 4f (L/D) (v2/2gc) ρ

Option B: 32 (μLV/gc D2)

Option C: 16/NRe

Option D: (fLρ/D) (v2/2gc)

Correct Answer: 32 (μLV/gc D2) ✔

Option A: 4(Ro-Ri)

Option B: √(Ro-Ri)

Option C: 2(Ro-Ri)

Option D: Ro + Ri

Correct Answer: 2(Ro-Ri) ✔

Option A: VX = V0 + q (x3/L2D)

Option B: VX = V0 + ⅓q (x3/L2)

Option C: VX = V0 + 2q (x2/LD)

Option D: VX = V0 + (4/3) q (x3/L2D)

Correct Answer: VX = V0 + (4/3) q (x3/L2D) ✔

Option A: Non-viscous

Option B: Viscous

Option C: Turbulent

Option D: Rotational

Correct Answer: Viscous ✔

Option A: Directly as the velocity

Option B: Inversely as the square of the velocity

Option C: Approximately as the square of the velocity

Option D: Inversely as the square of the diameter

Correct Answer: Approximately as the square of the velocity ✔

Option A: H

Option B: 12.6 H

Option C: 13.6 H

Option D: 14.6 H

Correct Answer: H ✔

Option A: Vacuum pumps

Option B: Blowers

Option C: Fans

Option D: Compressors

Correct Answer: Compressors ✔

Option A: First law of thermodynamics

Option B: Third law of thermodynamics

Option C: Law of conservation of momentum

Option D: None of these

Correct Answer: None of these ✔

Option A: Diffusion

Option B: Centrifugal

Option C: Jet ejector

Option D: Piston

Correct Answer: Diffusion ✔

Option A: Direction control

Option B: Back pressure

Option C: Relief

Option D: Pressure reduction

Correct Answer: Back pressure ✔

Option A: Also increases

Option B: Decreases

Option C: Remain constant

Option D: First decreases, and then increases

Correct Answer: First decreases, and then increases ✔

Option A: Increasing the acceleration head

Option B: Making the friction in pipe uniform

Option C: Decreasing the acceleration head

Option D: None of these

Correct Answer: Making the friction in pipe uniform ✔

Option A: Manometric

Option B: Total

Option C: Static

Option D: Friction

Correct Answer: Manometric ✔

Option A: High head

Option B: Low head but high discharge

Option C: Highly viscous liquid

Option D: Slurries of high solid concentration

Correct Answer: High head ✔

Option A: Suction

Option B: Delivery

Option C: Manometric

Option D: None of these

Correct Answer: None of these ✔

Option A: Static pressure

Option B: Dynamic pressure

Option C: Velocity at the stagnation point

Option D: All A., B. and C.

Correct Answer: D. All A., B. and C. ✔

Option A: A, C, D

Option B: B, D, E

Option C: A, B, E

Option D: A, D, E

Correct Answer: A, B, E ✔

Option A: Surface roughness and curvature (i.e. sharp corners)

Option B: Vibration

Option C: Pressure gradient and the compressibility of the flowing medium

Option D: All A., B. & C.

Correct Answer: D. All A., B. & C. ✔

Option A: Viscous forces are unimportant

Option B: Viscous forces control

Option C: Viscous forces control and inertial forces are unimportant

Option D: Gravity forces control

Correct Answer: Viscous forces control ✔

Option A: Globe valve

Option B: Gate valve

Option C: Needle valve

Option D: Butterfly valve

Correct Answer: Needle valve ✔

Option A: Pressure

Option B: Maximum velocity

Option C: Average velocity

Option D: Point velocity

Correct Answer: Average velocity ✔

Option A: Newtonian

Option B: Non-Newtonian

Option C: Ideal

Option D: Incompressible

Correct Answer: Newtonian ✔

Option A: V

Option B: V2

Option C: V4

Option D: V0.5

Correct Answer: V ✔

Option A: Hagen-Poiseuille’s equation

Option B: Stoke’s law

Option C: Navier-stokes equation

Option D: None of these

Correct Answer: Hagen-Poiseuille’s equation ✔

Option A: Inner diameter

Option B: Outer diameter

Option C: Thickness

Option D: Neither inner nor outer diameter

Correct Answer: Neither inner nor outer diameter ✔

Option A: Depends only on Reynolds number

Option B: Does not depend on Reynolds number

Option C: Depends on the roughness

Option D: None of these

Correct Answer: Depends only on Reynolds number ✔

Option A: Is independent of the compressibility of the fluid

Option B: Is dependent upon the viscosity of the fluid

Option C: Represents the conservation of mass

Option D: None of these

Correct Answer: Represents the conservation of mass ✔

Option A: Pseudo plastic

Option B: Bingham plastic

Option C: Dilatent

Option D: Newtonian

Correct Answer: Pseudo plastic ✔

Option A: N √Q/H3/4

Option B: N √Q/H2/3

Option C: N3D5/H1/3

Option D: N √Q/H

Correct Answer: N √Q/H3/4 ✔

Option A: R

Option B: R2

Option C: R4

Option D: R0.5

Correct Answer: R ✔

Option A: 1.3

Option B: 0.766

Option C: 0.87

Option D: None of these

Correct Answer: 0.766 ✔

Option A: Constant along a streamline

Option B: Not constant along a streamline

Option C: Increased in the direction of flow

Option D: None of these

Correct Answer: Not constant along a streamline ✔

Option A: Lρv2/D

Option B: LμV/D2

Option C: Dρv2/L

Option D: μV/L

Correct Answer: Lρv2/D ✔

Option A: Normal

Option B: Parallel

Option C: Tangential

Option D: None of these

Correct Answer: Normal ✔

Option A: I.D.

Option B: O.D.

Option C: Thickness

Option D: None of these

Correct Answer: I.D. ✔

Option A: 2xy/(x + y)

Option B: xy/(x + y)

Option C: (x + y)/2xy

Option D: (x + y)/xy

Correct Answer: 2xy/(x + y) ✔

Option A: More

Option B: Less

Option C: Equal

Option D: Independent of porosity

Correct Answer: Less ✔

Option A: Energy per unit mass

Option B: Energy per unit weight

Option C: Force per unit mass

Option D: None of these

Correct Answer: Energy per unit weight ✔

Option A: Vmax = 2Vav

Option B: Vmax = Vav

Option C: Vmax = 1.5Vav

Option D: Vmax = 0.5Vav

Correct Answer: Vmax = 2Vav ✔

Option A: Flow in straight lines only

Option B: Uniform flow

Option C: Steady uniform flow

Option D: Flow in which transverse components are zero

Correct Answer: Flow in which transverse components are zero ✔

Option A: Produces only radial current

Option B: Produces only tangential current

Option C: Is effective over wide range of viscosities

Option D: Does not produce tangential current

Correct Answer: Is effective over wide range of viscosities ✔

Option A: 0.5

Option B: 0.67

Option C: 1

Option D: 2

Correct Answer: 2 ✔

Option A: Always inversely proportional to the Reynolds number

Option B: Not dimensionless

Option C: Not dependent on the roughness of the pipe

Option D: None of these

Correct Answer: None of these ✔

Option A: Thermal conductivity

Option B: Electrical conductivity

Option C: Specific gravity

Option D: Electrical resistivity

Correct Answer: Electrical conductivity ✔

Option A: Centrifugal

Option B: Mixed flow

Option C: Axial flow

Option D: None of these

Correct Answer: Axial flow ✔

Option A: < 1

Option B: 1

Option C: > 1

Option D: 2

Correct Answer: < 1 ✔

Option A: Bingham plastic

Option B: Newtonian

Option C: Pseudo plastic

Option D: Dilatent

Correct Answer: Bingham plastic ✔

Option A: 15

Option B: 55

Option C: 155

Option D: 1050

Correct Answer: 55 ✔

Option A: Centrifugal

Option B: Reciprocating

Option C: Impulse

Option D: Parallel cylinder

Correct Answer: Impulse ✔

Option A: Flow velocity

Option B: Pressure

Option C: Total energy

Option D: All A., B. and C.

Correct Answer: Flow velocity ✔

Option A: Pipe becomes smoother with use

Option B: Friction factor increases linearly with time

Option C: Absolute roughness decreases with time

Option D: Absolute roughness increases linearly with time

Correct Answer: Absolute roughness increases linearly with time ✔

Option A: < 2100

Option B: < 0.1

Option C: > 2.5

Option D: < 500

Correct Answer: < 0.1 ✔

Option A: Small differential

Option B: Atmospheric

Option C: Absolute

Option D: Gage

Correct Answer: Small differential ✔

Option A: Venturimeter

Option B: Pitot tube

Option C: Rotameter

Option D: None of these

Correct Answer: Rotameter ✔

Option A: As square of

Option B: Directly as

Option C: As cube of

Option D: None of these

Correct Answer: As cube of ✔

Option A: Discharge and overall efficiency

Option B: Volume swept by piston for one complete revolution and the pressure in the cylinder

Option C: Angle swept by the crank pin at any instant and the discharge

Option D: None of these

Correct Answer: Volume swept by piston for one complete revolution and the pressure in the cylinder ✔

Option A: 33:3

Option B: 50

Option C: 66.6

Option D: 88.8

Correct Answer: 66.6 ✔

Option A: 25.61 kPa

Option B: 11.77 kPa

Option C: 14.86 kPa

Option D: 21.13 kPa

Correct Answer: 11.77 kPa ✔

Option A: Q∝N : H∝N2 : P∝N3

Option B: Q∝N2 : H∝N3 : P∝N

Option C: Q∝N : H∝N3 : P∝N2

Option D: Q∝N3 : H∝N : P∝N2

Correct Answer: Q∝N : H∝N2 : P∝N3 ✔

Option A: Inverse

Option B: Square root

Option C: Second power

Option D: First power

Correct Answer: Square root ✔

Option A: Non-sticky & non-corrosive nature

Option B: High vapour pressure

Option C: Low viscosity & surface tension

Option D: Low co-efficient of thermal expansion

Correct Answer: High vapour pressure ✔

Option A: Its capacity varies directly as the square of speed

Option B: Head varies as the square of speed

Option C: Horsepower input varies as the square of speed

Option D: Head varies as the speed

Correct Answer: Head varies as the square of speed ✔

Option A: Centrifugal

Option B: Reciprocating

Option C: Volute

Option D: Gear

Correct Answer: Centrifugal ✔

Option A: Pitot tube

Option B: Venturimeter

Option C: Orificemeter

Option D: Rotameter

Correct Answer: Pitot tube ✔

Option A: The S.I. unit of dynamic viscosity

Option B: The S.I. unit of kinematic viscosity

Option C: Equivalent to one poise

Option D: Equivalent to one stoke

Correct Answer: The S.I. unit of dynamic viscosity ✔

Option A: ML-2

Option B: MT-2

Option C: MLT-2

Option D: ML-2T

Correct Answer: MT-2 ✔

Option A: Increase

Option B: Decrease

Option C: Remain unchanged

Option D: Increase or decrease depending on the pipe material

Correct Answer: Increase ✔

Option A: Flow nozzle

Option B: Venturimeter

Option C: Rotameter

Option D: None of these

Correct Answer: Rotameter ✔

Option A: N

Option B: N/m

Option C: N/m2

Option D: N/m3

Correct Answer: N ✔

Option A: √x

Option B: 1/√x

Option C: x

Option D: 1/x

Correct Answer: √x ✔