Fluid Mechanics MCQs

Option A: The absolute roughness of a pipe de-creases with time

Option B: A pipe becomes smooth after using for long time

Option C: The friction factor decreases with time

Option D: The absolute roughness increases with time

Correct Answer: The absolute roughness increases with time ✔

Option A: gm/cm-sec2

Option B: dyne-sec/cm2

Option C: gm/cm2-sec

Option D: cm2/sec

Correct Answer: cm2/sec ✔

Option A: pressure

Option B: kinematic viscosity

Option C: dynamic viscosity

Option D: surface tension

Correct Answer: dynamic viscosity ✔

Option A: one which obeys Newton’s law of viscosity

Option B: frictionless and incompressible

Option C: very viscous

Option D: frictionless and compressible

Correct Answer: frictionless and incompressible ✔

Option A: 0.25

Option B: 0.50

Option C: 1.0

Option D: none of the above

Correct Answer: 1.0 ✔

Option A: decreases with increase in temperature

Option B: increases with increase in temperature

Option C: is independent of temperature

Option D: is independent of pressure for very high pressure intensities

Correct Answer: increases with increase in temperature ✔

Option A: intensity of pressure and rate of angular deformation

Option B: shear stress and rate of angular deformation

Option C: shear stress, viscosity and temperature

Option D: viscosity and rate of angular deformation

Correct Answer: shear stress and rate of angular deformation ✔

Option A: at the centroid of the submerged area

Option B: always above the centroid of the area

Option C: always below the centroid of the area

Option D: none of the above

Correct Answer: always below the centroid of the area ✔

Option A: 3.75 m

Option B: 4.0 m

Option C: 4.2m

Option D: 4.5m

Correct Answer: 4.2m ✔

Option A: when its metacentric height is zero

Option B: when the metacentre is above the centre of gravity

Option C: when the metacentre is below the centre of gravity

Option D: only when its centre of gravity is below its centre of buoyancy

Correct Answer: when the metacentre is above the centre of gravity ✔

Option A: rise until its weight equals the buoyant force

Option B: tend to move downward and it may finally sink

Option C: float

Option D: none of the above

Correct Answer: tend to move downward and it may finally sink ✔

Option A: (1) and (3)

Option B: (1)and(iv)

Option C: (2) and (3)

Option D: (2) and (4)

Correct Answer: (1)and(iv) ✔

Option A: center of gravity

Option B: center of buoyancy

Option C: center of pressure

Option D: metacentre

Correct Answer: center of pressure ✔

Option A: linearly with radial distance

Option B: as the square of the radial distance

Option C: inversely as the square of the radial distance

Option D: inversely as the radial distance

Correct Answer: as the square of the radial distance ✔

Option A: zero

Option B: one-fourth its value when cylinder was full

Option C: one-half its value when cylinder was full

Option D: cannot be predicted from the given data

Correct Answer: zero ✔

Option A: Coefficient of contraction of a venturimeter is unity

Option B: Flow nozzle is cheaper than venturimeter but has higher energy loss

Option C: Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined

Option D: None of the above statement is correct.

Correct Answer: None of the above statement is correct. ✔

Option A: (1) and (2)

Option B: (1)and(4)

Option C: (2) and (3)

Option D: (3) and (4)

Correct Answer: (1)and(4) ✔

Option A: The pressure intensity at vena contracta is atmospheric

Option B: Contraction is least at vena contracta

Option C: Stream lines are parallel throughout the jet at vena contracta

Option D: Coefficient of contraction is always less than one

Correct Answer: Stream lines are parallel throughout the jet at vena contracta ✔

Option A: (1) and (2)

Option B: (1)and(iv)

Option C: (2) and (3)

Option D: (2) and (4)

Correct Answer: (1)and(iv) ✔

Option A: 0

Option B: 1

Option C: 4/3

Option D: 2

Correct Answer: 1 ✔

Option A: (1) and (3)

Option B: (2) and (3)

Option C: (1) and (4)

Option D: (2) and (4)

Correct Answer: (2) and (4) ✔

Option A: 4/3

Option B: 3/2

Option C: 9/4

Option D: 27/8

Correct Answer: 9/4 ✔

Option A: x2y

Option B: x2-y2

Option C: cosx

Option D: x2 + y2

Correct Answer: x2-y2 ✔

Option A: directly proportional to its radial distance from axis of rotation

Option B: inversely proportional to its radial distance from the axis of rotation

Option C: inversely proportional to the square of its radial distance from the axis of rotation

Option D: directly proportional to the square of its radial distance from the axis of rotation

Correct Answer: directly proportional to its radial distance from axis of rotation ✔

Option A: mass

Option B: energy

Option C: momentum

Option D: none of the above

Correct Answer: mass ✔

Option A: velocity at stagnation point

Option B: stagnation pressure

Option C: static pressure

Option D: dynamic pressure

Correct Answer: stagnation pressure ✔

Option A: 0.611

Option B: 0.85

Option C: 0.98

Option D: 1.00

Correct Answer: 0.611 ✔

Option A: 5%

Option B: 10%

Option C: 15%

Option D: 20%

Correct Answer: 5% ✔

Option A: equal to atmospheric

Option B: less than atmospheric

Option C: more than atmospheric

Option D: none of the above

Correct Answer: less than atmospheric ✔

Option A: 0.611

Option B: 0.707

Option C: 0.855

Option D: 1.00

Correct Answer: 0.707 ✔

Option A: sudden enlargement

Option B: sudden contraction

Option C: gradual contraction or enlargement

Option D: friction

Correct Answer: friction ✔

Option A: sharp edged orifice

Option B: venturimeter

Option C: Borda’s mouthpiece running full

Option D: CipoUetti weir

Correct Answer: venturimeter ✔

Option A: H/3

Option B: H/2

Option C: 2 H/5

Option D: 2 H/3

Correct Answer: H/3 ✔

Option A: 300

Option B: 337.5

Option C: 600

Option D: 675

Correct Answer: 675 ✔

Option A: x

Option B: x

Option C: x

Option D: x/7

Correct Answer: x ✔

Option A: 0.423 D

Option B: 0.577 D

Option C: 0.223 D

Option D: 0.707 D

Correct Answer: 0.577 D ✔

Option A: at the extreme rear of body

Option B: at the extreme front of body

Option C: midway between rear and front of body

Option D: any where between rear and front of body depending upon Reynolds number

Correct Answer: at the extreme rear of body ✔

Option A: 0.223 R

Option B: 0.423 R

Option C: 0.577 R

Option D: 0.707 R

Correct Answer: 0.223 R ✔

Option A: a circular disc of plate held normal to flow

Option B: a sphere

Option C: a cylinder

Option D: a streamlined body

Correct Answer: a circular disc of plate held normal to flow ✔

Option A: constant

Option B: dependent only on Reynolds number

Option C: a function of Reynolds number and relative roughness

Option D: dependent on relative roughness only

Correct Answer: dependent only on Reynolds number ✔

Option A: directly proportional to Reynolds number and independent of pipe wall roughness

Option B: directly proportional to pipe wall roughness and independent of Reynolds number

Option C: inversely proportional to Reynolds number and indpendent of pipe wall roughness

Option D: inversely proportional to Reynolds number and directly proportional to pipe wall roughness

Correct Answer: inversely proportional to Reynolds number and indpendent of pipe wall roughness ✔

Option A: 1/2

Option B: 2/3

Option C: 3/2

Option D: 2

Correct Answer: 1/2 ✔

Option A: laminar flow

Option B: transition flow

Option C: turbulent flow

Option D: not predictable from the given data

Correct Answer: laminar flow ✔

Option A: is constant over the cross-section

Option B: varies linearly from zero at walls to maximum at centre

Option C: varies parabolically with maximum at the centre

Option D: none of the above

Correct Answer: varies parabolically with maximum at the centre ✔

Option A: laminar flow

Option B: transition flow

Option C: turbulent flow

Option D: critical flow

Correct Answer: turbulent flow ✔

Option A: 0

Option B: r/2

Option C: r

Option D: 2r

Correct Answer: r ✔

Option A: head loss and discharge are same in two systems

Option B: length of pipe and discharge are same in two systems

Option C: friction factor and length are same in two systems

Option D: length and diameter are same in two systems

Correct Answer: head loss and discharge are same in two systems ✔

Option A: the length of pipe

Option B: the viscosity of fluid

Option C: the bulk modulus for the fluid

Option D: the original head

Correct Answer: the bulk modulus for the fluid ✔

Option A: (1) and (2)

Option B: (1) and (3)

Option C: (2) and (3)

Option D: (1), (2) and (3)

Correct Answer: (2) and (3) ✔

Option A: 16/Re

Option B: 32/ Re

Option C: 64/ Re

Option D: none of the above where R,, is Reynolds number

Correct Answer: 64/ Re ✔

Option A: 1/3

Option B: 1/4

Option C: 1/2

Option D: 2/3

Correct Answer: 1/3 ✔

Option A: from reservoir A to reservoirs B and C

Option B: from reservoir B to reservoirs C and A

Option C: from reservoir C to reservoirs A and B

Option D: unpredictable

Correct Answer: from reservoir C to reservoirs A and B ✔

Option A: (1) and (3)

Option B: (2) and (3)

Option C: (1) and (4)

Option D: (2) and (4)

Correct Answer: (2) and (4) ✔

Option A: d > m > e

Option B: d > e > m

Option C: e > m > d

Option D: e > d > m

Correct Answer: e > d > m ✔

Option A: 0.40 cm

Option B: 0.20 cm

Option C: 0.10 cm

Option D: 0.05 cm

Correct Answer: 0.20 cm ✔

Option A: less than d

Option B: between d and 1.5 d

Option C: between 1.5 d and 2d

Option D: greater than 2d

Correct Answer: less than d ✔

Option A: 32 km

Option B: 20 km

Option C: 8 km

Option D: 4 km

Correct Answer: 32 km ✔

Option A: L/4

Option B: L/3

Option C: L/2

Option D: L

Correct Answer: L/4 ✔

Option A: 1 m

Option B: 10m

Option C: 100m

Option D: none of the above

Correct Answer: 100m ✔

Option A: the head loss is same through each pipe

Option B: the discharge is same through each pipe

Option C: a trial solution is not necessary

Option D: the discharge through each pipe is added to obtain total discharge

Correct Answer: the discharge is same through each pipe ✔

Option A: less than 1

Option B: between 1 and 100

Option C: 160

Option D: 200

Correct Answer: 160 ✔

Option A: always above the centre line of pipe

Option B: never above the energy grade line

Option C: always sloping downward in the direction of flow

Option D: all of the above

Correct Answer: never above the energy grade line ✔

Option A: always occurs before a separation point

Option B: always occurs after a separation point

Option C: is a region of high pressure intensity

Option D: none of the above

Correct Answer: always occurs after a separation point ✔

Option A: less than 1 m/sec

Option B: 1 m/sec

Option C: 1.5 m/sec

Option D: 2 m/sec

Correct Answer: 1 m/sec ✔

Option A: zero at the pipe wall

Option B: maximum at the pipe wall

Option C: independent of shear stress

Option D: none of the above

Correct Answer: zero at the pipe wall ✔

Option A: 1/3 R

Option B: 1/2 R

Option C: 2/3 R

Option D: 3/4R

Correct Answer: 1/3 R ✔

Option A: the pressure intensity reaches a minimum

Option B: the cross-section of a channel is reduced

Option C: the boundary layer comes to rest

Option D: all of the above

Correct Answer: the boundary layer comes to rest ✔

Option A: 0.1

Option B: 0.01

Option C: 0.001

Option D: 0.0001

Correct Answer: 0.01 ✔

Option A: a circular disc or plate held normal to flow

Option B: a sphere

Option C: a cylinder

Option D: an airfoil

Correct Answer: an airfoil ✔

Option A: highest intensity of pressure occurs around the circumference at right angles to flow

Option B: lowest pressure intensity occurs at front stagnation point

Option C: lowest pressure intensity occurs at rear stagnation point

Option D: total drag is zero

Correct Answer: total drag is zero ✔

Option A: log-log plot of friction factor against Reynolds number

Option B: log-log plot of relative roughness against Reynolds number

Option C: semi-log plot of friction factor against Reynolds number

Option D: semi-log plot of friction factor against relative roughness

Correct Answer: log-log plot of friction factor against Reynolds number ✔

Option A: velocity

Option B: discharge

Option C: head

Option D: pressure

Correct Answer: discharge ✔

Option A: x”7

Option B: x,/2

Option C: x4/5

Option D: x3/5

Correct Answer: x4/5 ✔

Option A: constant over the cross section

Option B: parabolic distribution across the section

Option C: zero at the mid plane and varies linearly with distance from mid plane

Option D: zero at plates and increases linearly to midpoint

Correct Answer: zero at the mid plane and varies linearly with distance from mid plane ✔

Option A: Lower critical Reynolds number is of no practical significance in pipe flow problems.

Option B: Upper critical Reynolds number is significant in pipe flow problems.

Option C: Lower critical Reynolds number has the value 2000 in pipe flow

Option D: Upper critical Reynolds number is the number at which turbulent flow changes to laminar flow

Correct Answer: A. Lower critical Reynolds number is of no practical significance in pipe flow problems ✔

Option A: H1/2

Option B: H3/2

Option C: H5/2

Option D: H

Correct Answer: H ✔

Option A: 1.00

Option B: 0.855

Option C: 0.7H

Option D: 0.611

Correct Answer: 1.00 ✔

Option A: slightly less

Option B: slightly more

Option C: nearly half

Option D: equal

Correct Answer: slightly less ✔

Option A: is independent of Reynolds number

Option B: decreases with higher Reynolds number

Option C: is equal to the coefficient of discharge of venturimeter

Option D: none of the above

Correct Answer: is equal to the coefficient of discharge of venturimeter ✔

Option A: H1/2

Option B: H3’2

Option C: H5/2

Option D: H5’4 where H is head

Correct Answer: H5/2 ✔

Option A: pipe diameter

Option B: throat diameter

Option C: angle of diverging section

Option D: both pipe diameter as well as throat diameter

Correct Answer: pipe diameter ✔

Option A: current meter

Option B: venturimeter

Option C: pitot tube

Option D: hotwire anemometer

Correct Answer: venturimeter ✔

Option A: discharge

Option B: velocity of gas

Option C: pressure intensity of gas

Option D: pressure intensity of liquid

Correct Answer: velocity of gas ✔

Option A: can be zero

Option B: is never zero

Option C: is always zero

Option D: is independent of coordinates

Correct Answer: can be zero ✔

Option A: steady flow

Option B: laminar flow

Option C: uniform flow

Option D: turbulent flow

Correct Answer: steady flow ✔

Option A: free vortex motion

Option B: forced vortex motion

Option C: free vortex at center and forced vortex outside

Option D: forced vortex at center and free vortex outside

Correct Answer: forced vortex at center and free vortex outside ✔

Option A: steady flow

Option B: uniform flow

Option C: incompressible flow

Option D: frictionless flow

Correct Answer: steady flow ✔

Option A: 1

Option B: 4/3

Option C: 2

Option D: 4

Correct Answer: 2 ✔

Option A: 22.5 m/sec

Option B: 33 m/sec

Option C: 40 m/sec

Option D: 90 m/sec

Correct Answer: 40 m/sec ✔

Option A: a function of temperature only

Option B: a physical property of the fluid.

Option C: dependent on the flow

Option D: independent of the flow

Correct Answer: dependent on the flow ✔

Option A: product of pressure intensity at its centroid and area

Option B: force on a vertical projection of the curved surface

Option C: weight of liquid vertically above the curved surface

Option D: force on the horizontal projection of the curved surface

Correct Answer: force on a vertical projection of the curved surface ✔

Option A: g/3

Option B: g/2

Option C: 2g/3

Option D: g

Correct Answer: g ✔

Option A: the pressure throughout the liquid mass is atmospheric

Option B: there will be vacuum in the liquid

Option C: the pressure in the liquid mass is greater than hydrostatic pressure

Option D: none of the above

Correct Answer: the pressure throughout the liquid mass is atmospheric ✔

Option A: 5kN

Option B: lOkN

Option C: 15 kN

Option D: 20 kN

Correct Answer: lOkN ✔

Option A: centre of gravity and centre of buoy-ancy

Option B: centre of gravity and metacentre

Option C: centre of buoyancy and metacentre

Option D: free surface and centre of buoyancy

Correct Answer: centre of gravity and metacentre ✔

Option A: coincides with the centre of gravity

Option B: coincides with the centroid of the volume of fluid displaced

Option C: remains above the centre of gravity

Option D: remains below the centre of gravity

Correct Answer: coincides with the centroid of the volume of fluid displaced ✔

Option A: PA

Option B: pA sin 9

Option C: pA cos 9

Option D: pA tan 9

Correct Answer: PA ✔

Option A: 4 kN/m2

Option B: 10 kN/m2

Option C: 12 kN/m2

Option D: 14 kN/m2

Correct Answer: 4 kN/m2 ✔