Explore topic-wise MCQs in Fluid Mechanics.

This section includes 88 Mcqs, each offering curated multiple-choice questions to sharpen your Fluid Mechanics knowledge and support exam preparation. Choose a topic below to get started.

51.

An object weighs 60 gm in air, 50 gm in water and 40 gm in oil. Then the specific gravity of the oil will be _____.

A. 0.25
B. 1
C. 1.5
D. 2
Answer» E.
52.

A liquid is compressed in a cylinder from a volume of 0.02 m3 at 200 N/m2 pressure to a volume of 0.01 m3 at 400 N/m2 pressure. The bulk modulus of elasticity of the liquid is

A. 500 N/m2
B. 1000 N/m2
C. 400 N/m2
D. 600 N/m2
Answer» D. 600 N/m2
53.

At constant temperature, the fluid whose viscosity does not change with the rate of deformation, is called:

A. Read fluid
B. Non-Newtonian fluid
C. Ideal fluid
D. Newtonian fluid
Answer» E.
54.

If for a fluid in motion, pressure at a point is same in all direction, then the fluid is

A. A real Fluid
B. A Newtonian Fluid
C. An Ideal Fluid
D. A non-Newtonian Fluid
Answer» D. A non-Newtonian Fluid
55.

Match List-I with List-II and choose the correct answer from the options given below List-I(Fluid property) List-II(Flow Phenomenon)A. Compressibilitya. The flow of real fluid past a tiny sphere B. Gravityb. CavitationC. Viscosityc. Hydraulic jumpD. Vapour pressure d. Flight of supersonic aircraft

A. A - c, B - d, C - b, D - a
B. A - c, B - d, C - a, D - b
C. A - d, B - c, C - a, D - b
D. A - d, B - c, C - b, D - a
Answer» D. A - d, B - c, C - b, D - a
56.

1.0 N/m2 is equal to:

A. 1.0 Pa
B. 1.0 kPa
C. 1.0 MPa
D. 1.0 bar
Answer» B. 1.0 kPa
57.

In the phenomenon of Cavitation, the characteristic fluid property involved is;

A. Surface tension
B. Viscosity
C. Bulk modulus of elasticity
D. Vapour pressure
Answer» E.
58.

In Red Wood Viscometer ______.

A. Absolute value of viscosity is determined
B. Part of the head of fluid is utilised in overcoming friction
C. Fluid discharges through orifice with negligible velocity
D. Comparison of viscosity is done
Answer» B. Part of the head of fluid is utilised in overcoming friction
59.

A Newtonian fluid is one which

A. is viscous but incompressible
B. has a linear relationship between the shear stress and the rate of angular deflection
C. exhibits an increase in viscosity with increasing rate of deformation
D. exhibits an decrease in viscosity with increasing rate of deformation
Answer» C. exhibits an increase in viscosity with increasing rate of deformation
60.

A steam turbine is supplied with steam at a pressure of 20 bar gauge. After expansion in the steam turbine, the steam passes to condenser which is maintained at a vacuum of 250 mm of mercury by means of pumps. The inlet and exhaust steam pressures will be nearly

A. 2101 kPa and 68 kPa
B. 2430 kPa and 78 kPa
C. 2101 kPa and 78 kPa
D. 2430 kPa and 68 kPa
Answer» B. 2430 kPa and 78 kPa
61.

Pseudo-plastic is a fluid for which

A. Dynamic viscosity decreases as the rate of shear increases
B. Newton’s law of viscosity holds good
C. Dynamic viscosity increases as the rate of shear increases
D. Dynamic viscosity increases with the time for which shearing forces are applied
Answer» B. Newton’s law of viscosity holds good
62.

A plate weighting 150 N and measuring 0.8 m × 0.8 m just slides down an inclined plane over an oil film of 1.2 mm thickness for an inclination of 30° and velocity of 0.2 m/s. Then the viscosity of the oil used is

A. 0.3 Ns/m2
B. 0.4 Ns/m2
C. 0.5 Ns/m2
D. 0.7 Ns/m2
Answer» E.
63.

Match List-I (Fluid properties) with List-II (Related terms) and select the correct answer using the given lists:List-IList-IIA. Capillaritya. CavitationB. Vapour pressureb. Density of waterC. Viscosityc. Shear forcesD. Specific gravityd. Surface tension

A. A-a, B-d, C-b, D-c
B. A-a, B-d, C-c, D-b
C. A-d, B-a, C-b, D-c
D. A-d, B-a, C-c, D-b
Answer» E.
64.

Alcohol is used as manometers because

A. it has low vapor pressure
B. it is clearly visible
C. it has low surface tension
D. it can provide longer column due to low density
Answer» E.
65.

Dynamic viscosity of water in comparison to mercury is

A. Higher
B. Lower
C. Same
D. Unpredictable
Answer» C. Same
66.

In the figure given above, for the ideal fluid, the curve that is applicable is:

A. A
B. B
C. C
D. D
Answer» B. B
67.

Dynamic viscosity increases with the rate of shear increase for

A. dilatant fluid
B. pseudoplastic fluid
C. rheopectic fluid
D. thixotropic fluid
Answer» B. pseudoplastic fluid
68.

An ideal fluid is one which is:

A. non-viscous
B. incompressible
C. incompressible and non-viscous
D. non-viscous and frictionless
Answer» D. non-viscous and frictionless
69.

Find the correct pair

A. Kinematic viscosity – ρ/µ (Density/dynamic viscosity)
B. Fluid of zero viscosity – Ideal fluid
C. Ideal fluid – kinematic viscosity
D. Viscous fluid – Fluid of zero viscosity
Answer» C. Ideal fluid – kinematic viscosity
70.

If no resistance is encountered by displacement, such a substance is known as _____.

A. Fluid
B. Water
C. Gas
D. Ideal Fluid
Answer» E.
71.

Ideal fluid is one which has no

A. Viscosity
B. Surface tension
C. Both viscosity and surface tension
D. None of the options
Answer» D. None of the options
72.

Poise can also be expressed as

A. Dyne-cm/s2
B. Dyne-cm/s
C. Dyne-s/cm
D. Dyne-s/cm2
Answer» E.
73.

Kinematic viscosity is equal to :

A. Dynamic viscosity/density
B. Dynamic viscosity × density
C. Density/dynamic viscosity
D. 1/dynamic viscosity × density
Answer» B. Dynamic viscosity × density
74.

Kinematic viscosity of air at 20°C is given to be 1.6 × 10-5 m2/s. Its kinematic viscosity at 70°C will be approximately

A. 2.2 × 10-5 m2/s
B. 1.6 × 10-5 m2/s
C. 1.2 × 10-5 m2/s
D. 3.2 × 10-5 m2/s
Answer» B. 1.6 × 10-5 m2/s
75.

'Kinematic viscosity' is dimensionally represented as

A. \(\frac{T^2}{L}\)
B. \(\frac{L^2}{T}\)
C. \(\frac{M}{L^2T}\)
D. \(\frac{M}{LT}\)
Answer» C. \(\frac{M}{L^2T}\)
76.

Kinematic viscosity of gases on increase of temperature

A. Decreases
B. Increases
C. Remains the same
D. First decreases then increases
Answer» C. Remains the same
77.

A moving fluid mass may be brought to a static equilibrium position by applying an imaginary inertia force of the same magnitude as that of the accelerating force but in the opposite direction. This statement is called

A. Pascal’s law
B. Archimedes’ principle
C. D’Alembert’s principle
D. None of these
Answer» D. None of these
78.

According to Newton’s law of viscosity, shear stress is:

A. directly proportional to the velocity
B. inversely proportional to the velocity
C. directly proportional to the velocity gradient
D. directly proportional to viscosity
Answer» D. directly proportional to viscosity
79.

One poise is equivalent to:

A. 1 kg/m-hr
B. 1 gm/cm-sec
C. 98 dyne/sec
D. 68 kgf-sec/m2
Answer» C. 98 dyne/sec
80.

Floating logs of wood tend to move to thy' mid-river reach on the water surface. This is due to

A. Least obstruction from the banks
B. 2-cell transverse circulation in the flow
C. Fastest velocity along the mid-river reach
D. Near-symmetry of the isovels across the section is conducive to principle of least work
Answer» C. Fastest velocity along the mid-river reach
81.

Pick the correct statement about the bulk modulus of elasticity:

A. it is a dimensionless number
B. it is independent of pressure and viscosity
C. it is larger if fluid is more compressible
D. it is higher if the fluid is less compressible
Answer» E.
82.

Bulk modulus of elasticity.

A. is independent of temperature
B. increases with pressure
C. is independent of pressure and viscosity
D. is larger when fluid is more compressible
Answer» C. is independent of pressure and viscosity
83.

A fluid whose shear stress is linearly proportional to the velocity gradient in the direction perpendicular to the plane of shear is called as _______.

A. Friction fluid
B. Stress fluid
C. Newtonian fluid
D. Cartesian fluid
Answer» D. Cartesian fluid
84.

_________ is NOT a property of fluid.

A. Specific weight
B. Area
C. Specific volume
D. Mass density
Answer» C. Specific volume
85.

In a Newtonian fluid, the shear stress

A. is inversely proportional to the strain
B. is directly proportional to rate of shear strain
C. balances pressure
D. balances inertia stress
Answer» C. balances pressure
86.

A liquid compressed in a cylinder has a volume of 0.04 m3 at 100 kg/cm2 and a volume of 0.039 m3 at 200 kg/cm2. The bulk modulus of elasticity of liquid is

A. 4000 kg/cm2
B. 400 kg/cm2
C. 40 × 105 kg/cm2
D. 40 × 106 kg/cm2
Answer» B. 400 kg/cm2
87.

If the specific gravity of oil is 0.7, then its density in kg/m3 will be ______

A. 70
B. 700
C. 7
D. 7000
Answer» C. 7
88.

An iceberg floats in sea water with 14% of its volume projecting above the sea surface. If the specific weight of sea water is 10400 N/m3, determine the specific weight of the iceberg (in N/m3 units).

A. 9125
B. 8836
C. 8314
D. 8944
Answer» E.