1000+ Fluid Mechanics MCQ for SSC JHT [Solved]
Thursday 9th of March 2023
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1. Bernoulli equation deals with the law of conservation of
A. Mass
B. Momentum
C. Energy
D. Work
Answer : C
A. Mass
B. Momentum
C. Energy
D. Work
Answer : C
2. The Francis formula for the discharge over Cipoletti weir is
A. 1.84 LH1/2
B. 1.84 LH
C. 1.84 LH3/2
D. 1.84 LH5/2
Answer : C
A. 1.84 LH1/2
B. 1.84 LH
C. 1.84 LH3/2
D. 1.84 LH5/2
Answer : C
3. If the depth of water in an open channel is greater than the critical depth, the flow is called
A. Critical flow
B. Turbulent flow
C. Tranquil flow
D. Torrential flow
Answer : C
A. Critical flow
B. Turbulent flow
C. Tranquil flow
D. Torrential flow
Answer : C
4. The magnitude of water hammer depends upon the
A. Elastic properties of the pipe material
B. Elastic properties of the liquid flowing through the pipe
C. Speed at which the valve is closed
D. All of the above
Answer : D
A. Elastic properties of the pipe material
B. Elastic properties of the liquid flowing through the pipe
C. Speed at which the valve is closed
D. All of the above
Answer : D
5. Coefficient of discharge Cd is equal to (where Cc = Coefficient of contraction, Cv = Coefficient of velocity, and Cr = Coefficient of resistance)
A. Cc × Cv
B. Cc × Cr
C. Cv × Cr
D. Cc/Cr
Answer : A
A. Cc × Cv
B. Cc × Cr
C. Cv × Cr
D. Cc/Cr
Answer : A
6. According to Bernoulli's equation
A. Z + p/w + v²/2g = constant
B. Z + p/w - v²/2g = constant
C. Z - p/w + v²/2g = constant
D. Z - p/w - v²/2g = constant
Answer : A
A. Z + p/w + v²/2g = constant
B. Z + p/w - v²/2g = constant
C. Z - p/w + v²/2g = constant
D. Z - p/w - v²/2g = constant
Answer : A
7. The Euler's equation for the motion of liquids is based upon the assumption that
A. The fluid is non - viscous, homogeneous and incompressible
B. The velocity of flow is uniform over the section
C. The flow is continuous, steady and along the stream line
D. All of the above
Answer : D
A. The fluid is non - viscous, homogeneous and incompressible
B. The velocity of flow is uniform over the section
C. The flow is continuous, steady and along the stream line
D. All of the above
Answer : D
8. The loss of head at exit of a pipe is (where v = Velocity of liquid in the pipe)
A. v²/2g
B. 0.5v²/2g
C. 0.375v²/2g
D. 0.75v²/2g
Answer : A
A. v²/2g
B. 0.5v²/2g
C. 0.375v²/2g
D. 0.75v²/2g
Answer : A
9. In a free nappe,
A. The pressure below the nappe is atmospheric
B. The pressure below the nappe is negative
C. The pressure above the nappe is atmospheric
D. The pressure above the nappe is negative
Answer : A
A. The pressure below the nappe is atmospheric
B. The pressure below the nappe is negative
C. The pressure above the nappe is atmospheric
D. The pressure above the nappe is negative
Answer : A
10. A piece weighing 3 kg in air was found to weigh 2.5 kg when submerged in water. Its specific gravity is
A. 1
B. 5
C. 7
D. 6
Answer : D
A. 1
B. 5
C. 7
D. 6
Answer : D
11. The velocity through a channel of circular section will be maximum when the depth of water is __________ the diameter of the circular channel.
A. 0.34 times
B. 0.67 times
C. 0.81 times
D. 0.95 times
Answer : C
A. 0.34 times
B. 0.67 times
C. 0.81 times
D. 0.95 times
Answer : C
12. The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a rectangular notch is given by
A. dQ/Q = (1/2) × (dH/H)
B. dQ/Q = (3/4) × (dH/H)
C. dQ/Q = (dH/H)
D. dQ/Q = (3/2) × (dH/H)
Answer : D
A. dQ/Q = (1/2) × (dH/H)
B. dQ/Q = (3/4) × (dH/H)
C. dQ/Q = (dH/H)
D. dQ/Q = (3/2) × (dH/H)
Answer : D
13. At the center line of a pipe flowing under pressure where the velocity gradient is zero, the shear stress will be
A. Minimum
B. Maximum
C. Zero
D. Could be any value
Answer : D
A. Minimum
B. Maximum
C. Zero
D. Could be any value
Answer : D
14. The flow in a pipe or channel is said to be uniform when
A. The liquid particles at all sections have the same velocities
B. The liquid particles at different sections have different velocities
C. The quantity of liquid flowing per second is constant
D. Each liquid particle has a definite path
Answer : A
A. The liquid particles at all sections have the same velocities
B. The liquid particles at different sections have different velocities
C. The quantity of liquid flowing per second is constant
D. Each liquid particle has a definite path
Answer : A
15. Buoyant force is
A. Resultant force acting on a floating body
B. Equal to the volume of liquid displaced
C. Force necessary to keep a body in equilibrium
D. The resultant force on a body due to the fluid surrounding it
Answer : D
A. Resultant force acting on a floating body
B. Equal to the volume of liquid displaced
C. Force necessary to keep a body in equilibrium
D. The resultant force on a body due to the fluid surrounding it
Answer : D
16. The dynamic viscosity of gases __________ with rise in temperature.
A. Remain unaffected
B. Increases
C. Decreases
D. None of these
Answer : B
A. Remain unaffected
B. Increases
C. Decreases
D. None of these
Answer : B
17. Ratio of inertia force to elastic force is known as
A. Mach number
B. Froude number
C. Reynolds number
D. Weber's number
Answer : A
A. Mach number
B. Froude number
C. Reynolds number
D. Weber's number
Answer : A
18. In order to measure the flow with a Venturimeter, it is installed in
A. Horizontal line
B. Inclined line with flow upwards
C. Inclined line with flow downwards
D. Any direction and in any location
Answer : D
A. Horizontal line
B. Inclined line with flow upwards
C. Inclined line with flow downwards
D. Any direction and in any location
Answer : D
19. Fluid is a substance that
A. Cannot be subjected to shear forces
B. Always expands until it fills any container
C. Has the same shear stress at a point regardless of its motion
D. Cannot remain at rest under action of any shear force
Answer : D
A. Cannot be subjected to shear forces
B. Always expands until it fills any container
C. Has the same shear stress at a point regardless of its motion
D. Cannot remain at rest under action of any shear force
Answer : D
20. A submerged body is said to be in a stable equilibrium, if its centre of gravity __________ the centre of buoyancy.
A. Coincides with
B. Lies below
C. Lies above
D. None of these
Answer : B
A. Coincides with
B. Lies below
C. Lies above
D. None of these
Answer : B
21. The flow which neglects changes in a transverse direction is known as
A. One dimensional flow
B. Uniform flow
C. Steady flow
D. Turbulent flow
Answer : A
A. One dimensional flow
B. Uniform flow
C. Steady flow
D. Turbulent flow
Answer : A
22. When a tube of smaller diameter is dipped in water, the water rises in the tube with an upward __________ surface.
A. Concave
B. Convex
C. Plane
D. None of these
Answer : A
A. Concave
B. Convex
C. Plane
D. None of these
Answer : A
23. The divergent portion of a Venturimeter is made longer than convergent portion in order to
A. Avoid the tendency of breaking away the stream of liquid
B. To minimise frictional losses
C. Both (A) and (B)
D. None of these
Answer : C
A. Avoid the tendency of breaking away the stream of liquid
B. To minimise frictional losses
C. Both (A) and (B)
D. None of these
Answer : C
24. According to Francis formula, the discharge over a rectangular weir is (where n = Number of end contractions)
A. (2/3) × Cd (L - nH) × ?(2gh)
B. (2/3) × Cd (L - 0.1nH) × ?(2g) × H3/2
C. (2/3) × Cd (L - nH) × ?(2g) × H²
D. (2/3) × Cd (L - nH) × ?(2g) × H5/2
Answer : B
A. (2/3) × Cd (L - nH) × ?(2gh)
B. (2/3) × Cd (L - 0.1nH) × ?(2g) × H3/2
C. (2/3) × Cd (L - nH) × ?(2g) × H²
D. (2/3) × Cd (L - nH) × ?(2g) × H5/2
Answer : B
25. The vapour pressure over the concave surface is
A. Less man the vapour pressure over the plane surface
B. Equal to the vapour pressure over the plane surface
C. Greater than the vapour pressure over the plane surface
D. Zero
Answer : A
A. Less man the vapour pressure over the plane surface
B. Equal to the vapour pressure over the plane surface
C. Greater than the vapour pressure over the plane surface
D. Zero
Answer : A
26. Mach number is significant in
A. Supersonics, as with projectiles and jet propulsion
B. Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. Simultaneous motion through two fluids where there is a surface of discontinuity, gravity force, and wave making effects, as with ship's hulls
D. All of the above
Answer : A
A. Supersonics, as with projectiles and jet propulsion
B. Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. Simultaneous motion through two fluids where there is a surface of discontinuity, gravity force, and wave making effects, as with ship's hulls
D. All of the above
Answer : A
27. Rotameter is a device used to measure
A. Absolute pressure
B. Velocity of fluid
C. Flow
D. Rotation
Answer : C
A. Absolute pressure
B. Velocity of fluid
C. Flow
D. Rotation
Answer : C
28. The discharge over a rectangular notch is
A. Inversely proportional to H3/2
B. Directly proportional to H3/2
C. Inversely proportional to H5/2
D. Directly proportional to H5/2
Answer : B
A. Inversely proportional to H3/2
B. Directly proportional to H3/2
C. Inversely proportional to H5/2
D. Directly proportional to H5/2
Answer : B
29. The ratio of the inertia force to the __________ is called Euler's number.
A. Pressure force
B. Elastic force
C. Surface tension force
D. Viscous force
Answer : A
A. Pressure force
B. Elastic force
C. Surface tension force
D. Viscous force
Answer : A
30. The coefficient of venturi-flume, generally, lies between
A. 0.3 to 0.45
B. 0.50 to 0.75
C. 0.75 to 0.95
D. 0.95 to 1.0
Answer : D
A. 0.3 to 0.45
B. 0.50 to 0.75
C. 0.75 to 0.95
D. 0.95 to 1.0
Answer : D
31. Non uniform flow occurs when
A. The direction and magnitude of the velocity at all points are identical
B. The velocity of successive fluid particles, at any point, is the same at successive periods of time
C. Velocity, depth, pressure, etc. change from point to point in the fluid flow.
D. The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Answer : C
A. The direction and magnitude of the velocity at all points are identical
B. The velocity of successive fluid particles, at any point, is the same at successive periods of time
C. Velocity, depth, pressure, etc. change from point to point in the fluid flow.
D. The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
Answer : C
32. Differential manometer is used to measure
A. Pressure in pipes, channels etc.
B. Atmospheric pressure
C. Very low pressure
D. Difference of pressure between two points
Answer : D
A. Pressure in pipes, channels etc.
B. Atmospheric pressure
C. Very low pressure
D. Difference of pressure between two points
Answer : D
33. Free surface of a liquid tends to contract to the smallest possible area due to force of
A. Surface tension
B. Viscosity
C. Friction
D. Cohesion
Answer : A
A. Surface tension
B. Viscosity
C. Friction
D. Cohesion
Answer : A
34. In a free vortex motion, the radial component of velocity everywhere is
A. Maximum
B. Minimum
C. Zero
D. Nonzero and finite
Answer : C
A. Maximum
B. Minimum
C. Zero
D. Nonzero and finite
Answer : C
35. An open tank containing liquid is moving with an acceleration on an inclined plane. The inclination of the free surface of the liquid will be __________ to the acceleration of the tank.
A. Equal to
B. Directly proportional
C. Inversely proportional
D. None of these
Answer : B
A. Equal to
B. Directly proportional
C. Inversely proportional
D. None of these
Answer : B
36. The speed of sound in a ideal gas varies directly as its
A. Absolute temperature
B. Temperature
C. Density
D. Modulus of elasticity
Answer : A
A. Absolute temperature
B. Temperature
C. Density
D. Modulus of elasticity
Answer : A
37. Principle of similitude forms the basis of
A. Comparing two identical equipments
B. Designing models so that the result can be converted to prototypes
C. Comparing similarity between design and actual equipment
D. Hydraulic designs
Answer : B
A. Comparing two identical equipments
B. Designing models so that the result can be converted to prototypes
C. Comparing similarity between design and actual equipment
D. Hydraulic designs
Answer : B
38. The height of a water column equivalent to a pressure of 0.15 MPa is
A. 15.3 m
B. 25.3 m
C. 35.3 m
D. 45.3 m
Answer : A
A. 15.3 m
B. 25.3 m
C. 35.3 m
D. 45.3 m
Answer : A
39. A tank of uniform cross-sectional area (A) containing liquid upto height (H1) has an orifice of cross-sectional area (a) at its bottom. The time required to bring the liquid level from H1 to H2 will be
A. 2A × ?H?/Cd × a × ?(2g)
B. 2A × ?H?/Cd × a × ?(2g)
C. 2A × (?H? - ?H?)/Cd × a × ?(2g)
D. 2A × (?H3/2 - ?H3/2)/Cd × a × ?(2g)
Answer : C
A. 2A × ?H?/Cd × a × ?(2g)
B. 2A × ?H?/Cd × a × ?(2g)
C. 2A × (?H? - ?H?)/Cd × a × ?(2g)
D. 2A × (?H3/2 - ?H3/2)/Cd × a × ?(2g)
Answer : C
40. The point at which the resultant pressure on an immersed surface acts, is known as
A. Centre of gravity
B. Centre of depth
C. Centre of pressure
D. Centre of immersed surface
Answer : C
A. Centre of gravity
B. Centre of depth
C. Centre of pressure
D. Centre of immersed surface
Answer : C
41. The siphon will work satisfactorily, if the minimum pressure in the pipe is __________ vapour pressure of liquid.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : C
A. Equal to
B. Less than
C. More than
D. None of these
Answer : C
42. The discharge in an open channel corresponding to critical depth is
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : C
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : C
43. Density of water is maximum at
A. 0° C
B. 0° K
C. 4° C
D. 100° C
Answer : C
A. 0° C
B. 0° K
C. 4° C
D. 100° C
Answer : C
44. The value of coefficient of discharge is __________ the value of coefficient of velocity.
A. Less than
B. Same as
C. More than
D. None of these
Answer : A
A. Less than
B. Same as
C. More than
D. None of these
Answer : A
45. Free surface of a liquid behaves like a sheet and tends to contract to smallest possible area due to the
A. Force of adhesion
B. Force of cohesion
C. Force of friction
D. Force of diffusion
Answer : B
A. Force of adhesion
B. Force of cohesion
C. Force of friction
D. Force of diffusion
Answer : B
46. The volumetric change of the fluid caused by a resistance is known as
A. Volumetric strain
B. Volumetric index
C. Compressibility
D. Adhesion
Answer : C
A. Volumetric strain
B. Volumetric index
C. Compressibility
D. Adhesion
Answer : C
47. The tendency of a liquid surface to contract is due to the following property
A. Cohesion
B. Adhesion
C. Viscosity
D. Surface tension
Answer : D
A. Cohesion
B. Adhesion
C. Viscosity
D. Surface tension
Answer : D
48. Liquids
A. Cannot be compressed
B. Occupy definite volume
C. Are not affected by change in pressure and temperature
D. None of the above
Answer : D
A. Cannot be compressed
B. Occupy definite volume
C. Are not affected by change in pressure and temperature
D. None of the above
Answer : D
49. Which of the following meters is not associated with viscosity?
A. Red wood
B. Say bolt
C. Engler
D. Orsat
Answer : D
A. Red wood
B. Say bolt
C. Engler
D. Orsat
Answer : D
50. For pipes, laminar flow occurs when Reynolds number is
A. Less than 2000
B. Between 2000 and 4000
C. More than 4000
D. Less than 4000
Answer : A
A. Less than 2000
B. Between 2000 and 4000
C. More than 4000
D. Less than 4000
Answer : A