IN THIS PAGE WE WILL Post 2 OBJECTIVE QUESTIONS DAILY...YOU CAN LEARN HERE ANY THING VERY EASILY WITH FULL EXPLANATION.
1. One litre of water occupies a volume of
A. 100 cm3
B. 250 cm3
C. 500 cm3
D. 1000 cm3
Answer: Option D
Explanation: 1000 litre=1 m3= 100 cm x 100 cm x 100 cm =1,000,000 cm3
So 1 litre=1,000,000/1,000=1000cm3.
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2. The fluid property, due to which, mercury does not wet the glass is
A. surface tension
B. viscosity
C. cohesion
D. adhesion
Answer: Option A
Explanation: surface tension of any fluid particle acts radially over the tangential components so that the fluid particles try to obtain a minimal surface area. In this stake the mercury droplet gets spherical and thus have minimum contact just at only one point on the glass....
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3.Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds
A. 4000 B. 2100
C. 1500 D. 3000
Answer: Option B
Explanation: For flow in a conduit:
Re < 2100 Laminar Flow Sheer Stress depends on viscosity but not on density.
2100 < Re < 4000 : Transient Flow
Re > 4000 Turbulent flow depends on density.
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A. jet pump
Answer: Option A
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5. The normal stress is the same in all directions at a point in a fluid, when the fluid is
A. non-viscous.
B. incompressible.
C. both (a) and (b).
D. having no motion of one fluid layer relative to the other.
Answer: Option D
Explanation: When a fluid is in motion shear stresses are developed if the particles of the fluid move relative to one another. When this happens adjacent particles have different velocities. If fluid velocity is the same at every point then there is no shear stress produced: the particles have zero relative velocity.
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6.Head developed by a centrifugal pump depends on its
A. speed
B. impeller diameter
C. both (a) and (b)
D. neither (a) nor (b)
Answer: Option C
Explanation: When the speed and impeller's dia is high then high vacuum create inside the impeller and a good head is develop.
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4. When the momentum of one fluid is used for moving
another fluid, such a device is called a/an:
A. jet pump
B. blower
C. acid egg
D. none of these
Answer: Option A
Explanation: This a vacuum jet ejector & works
under principle.
Velocity is directly prop to under root of delta P
(pressure drop).
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5. The normal stress is the same in all directions at a point in a fluid, when the fluid is
A. non-viscous.
B. incompressible.
C. both (a) and (b).
D. having no motion of one fluid layer relative to the other.
Answer: Option D
Explanation: When a fluid is in motion shear stresses are developed if the particles of the fluid move relative to one another. When this happens adjacent particles have different velocities. If fluid velocity is the same at every point then there is no shear stress produced: the particles have zero relative velocity.
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6.Head developed by a centrifugal pump depends on its
A. speed
B. impeller diameter
C. both (a) and (b)
D. neither (a) nor (b)
Answer: Option C
Explanation: When the speed and impeller's dia is high then high vacuum create inside the impeller and a good head is develop.
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7. The head loss in
turbulent flow in a pipe varies
A. as velocity
B. as (velocity)2
C. inversely as the square of diameter
D. inversely as the velocity
Answer: Option B
Explanation: h=4flv2 / 2gd
For turbulent flow f = 0.079/Re0.25
Re=dvp/u
h directly proportional to v1.75
nearly equal to 2
Ans [B]
A. as velocity
B. as (velocity)2
C. inversely as the square of diameter
D. inversely as the velocity
Answer: Option B
Explanation: h=4flv2 / 2gd
For turbulent flow f = 0.079/Re0.25
Re=dvp/u
h directly proportional to v1.75
nearly equal to 2
Ans [B]
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8. Most commonly
used joint in the underground pipe lines is the
A. sleeve joint
B. coupling
C. flange
D. expansion joint
Answer: Option A
Explanation: A sleeve joint is device for joining the ends of two wires or cables together, constructed by forcing the ends of the wires or cables into both ends of a hollow sleeve. And hence this joint is suitable for underground pipelines.
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B. coupling
C. flange
D. expansion joint
Answer: Option A
Explanation: A sleeve joint is device for joining the ends of two wires or cables together, constructed by forcing the ends of the wires or cables into both ends of a hollow sleeve. And hence this joint is suitable for underground pipelines.
9. With increasing
flow rate, the hydraulic efficiency of a centrifugal pump
A. monotonically decreases.
B. decreases and then increases.
C. remains constant.
D. increases and then decreases.
Answer: Option A
Explanation: In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves the given order. This concept first arose in calculus, and was later generalized to the more abstract setting of order theory.
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B. decreases and then increases.
C. remains constant.
D. increases and then decreases.
Answer: Option A
Explanation: In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves the given order. This concept first arose in calculus, and was later generalized to the more abstract setting of order theory.
10. The velocity
profile for turbulent flow through a closed conduit is
A. logarithmic
B. parabolic
C. hyperbolic
D. linear
Answer: Option A
Explanation: As it is turbulent flow the velocity profile is neither parabolic nor linear. And as it flows with high velocity its velocity profile must be logarithmic
A. logarithmic
B. parabolic
C. hyperbolic
D. linear
Answer: Option A
Explanation: As it is turbulent flow the velocity profile is neither parabolic nor linear. And as it flows with high velocity its velocity profile must be logarithmic
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A. bursting of pipelines due to closure by a valve.
B. rapid pressure change due to a rapid change in the rate of flow.
C. pressure increase due to closure of a valve resulting in decrease in rate of flow.
D. none of these.
Answer: Option B
Explanation: Water hammer (or, more generally, fluid hammer) is a pressure surge or wave caused when a fluid (usually a liquid but sometimes also a gas) in motion is forced to stop or change direction suddenly (momentum change). Water hammer commonly occurs when a valve closes suddenly at an end of a pipeline system, and a pressure wave propagates in the pipe. It is also called hydraulic shock.
11. Water hammer in
a pipeline results from the-
A. bursting of pipelines due to closure by a valve.
B. rapid pressure change due to a rapid change in the rate of flow.
C. pressure increase due to closure of a valve resulting in decrease in rate of flow.
D. none of these.
Answer: Option B
Explanation: Water hammer (or, more generally, fluid hammer) is a pressure surge or wave caused when a fluid (usually a liquid but sometimes also a gas) in motion is forced to stop or change direction suddenly (momentum change). Water hammer commonly occurs when a valve closes suddenly at an end of a pipeline system, and a pressure wave propagates in the pipe. It is also called hydraulic shock.
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12. Which of the
following denotes the effect of compressibility in fluid flow?
A. Weber number
B. Mach number
C. Euler number
D. Reynolds number
Answer: Option B
Explanation: Reynolds number: Inertial forces/ viscous forces,
Mach number: Inertial forces/ elastic forces,
Euler number: Pressure forces / inertial forces,
Weber number: Inertial forces/ Surface tension.
A. Weber number
B. Mach number
C. Euler number
D. Reynolds number
Answer: Option B
Explanation: Reynolds number: Inertial forces/ viscous forces,
Mach number: Inertial forces/ elastic forces,
Euler number: Pressure forces / inertial forces,
Weber number: Inertial forces/ Surface tension.
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13. Nominal size of the
discharge pipe of a pump is usually __________ the nominal size of the inlet
pipe
A. smaller than
B. larger than
C. same as
D. twice
Answer : Option A
A. smaller than
B. larger than
C. same as
D. twice
Answer : Option A
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14. The terminal
velocity of a small sphere settling in a viscous fluid varies as the
A. first power of its dimeter.
B. inverse of the fluid viscosity.
C. inverse square of the diameter.
D. square of the difference in specific weights of solid & fluid.
Answer : Option B
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A. first power of its dimeter.
B. inverse of the fluid viscosity.
C. inverse square of the diameter.
D. square of the difference in specific weights of solid & fluid.
Answer : Option B
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15. If the
discharge of a centrifugal pump is throttled, then its suction lift
A. increases
B. decreases
C. remains unchanged
D. data insufficient to predict
Answer: Option A
A. increases
B. decreases
C. remains unchanged
D. data insufficient to predict
Answer: Option A
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16. At high
Reynolds number
A. inertial forces control and viscous forces are unimportant.
B. viscous forces predominate.
C. inertial forces are unimportant and viscous forces control.
D. none of these.
Answer: Option A
A. inertial forces control and viscous forces are unimportant.
B. viscous forces predominate.
C. inertial forces are unimportant and viscous forces control.
D. none of these.
Answer: Option A
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17. Foot valves
provided in pumps are __________ valves.
A. relief
B. three/four way
C. pressure reducing
D. directional control
Answer: Option D
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A. relief
B. three/four way
C. pressure reducing
D. directional control
Answer: Option D
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18. What
causes cavitation in centrifugal pump?
A. High suction pressure
B. Low barometric pressure
C. Low suction pressure
D. High suction velocity
A. High suction pressure
B. Low barometric pressure
C. Low suction pressure
D. High suction velocity
Answer: Option C
Explanation: Local boiling of liquid due to increase in velocity is called cavitation. As the velocity increase the pressure falls. The decrease in pressure cause boiling of the liquid in a flow. Thus low suction pressure in centrifugal pump with high velocity causes cavitation.
Explanation: Local boiling of liquid due to increase in velocity is called cavitation. As the velocity increase the pressure falls. The decrease in pressure cause boiling of the liquid in a flow. Thus low suction pressure in centrifugal pump with high velocity causes cavitation.
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19.Two dimensional stream function
A. relates velocity and pressure.
B. is constant along a stream line.
C. is constant along an equipotential surface.
D. none of these.
Answer: Option B
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Answer- When concrete is loaded, the structure undergoes elastic and inelastic deformations. Elastic deformations occur immediately after the concrete is subjected to a given load, according to Hooke’s Law. Inelastic deformations increase with time as the concrete experiences a sustained load. This inelastic deformation, also known as creep, increases at a decreasing rate during the loading period. During the first month of sustained loading, approximately one-fourth to one-third of the ultimate creep takes place. As time proceeds, usually one-half to three-fourths of the ultimate creep occurs during the first half year.
A. relates velocity and pressure.
B. is constant along a stream line.
C. is constant along an equipotential surface.
D. none of these.
Answer: Option B
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MOST ARISING
INTERVIEW QUESTION
Q. What is Creep?
Answer- When concrete is loaded, the structure undergoes elastic and inelastic deformations. Elastic deformations occur immediately after the concrete is subjected to a given load, according to Hooke’s Law. Inelastic deformations increase with time as the concrete experiences a sustained load. This inelastic deformation, also known as creep, increases at a decreasing rate during the loading period. During the first month of sustained loading, approximately one-fourth to one-third of the ultimate creep takes place. As time proceeds, usually one-half to three-fourths of the ultimate creep occurs during the first half year.
The
amount of creep that the concrete undergoes is dependent upon 1) the magnitude
of the sustained loading, 2) the age and strength of the concrete when the
stress is applied, and 3) the total amount of time that the concrete is
stressed. When the concrete is loaded, the specimen undergoes internal
properties such as closure of voids in the concrete, viscous flow of the
cement-water paste, crystalline flow in aggregates, and water flowing out of
the cement "gel" due to drying and loading. Aggregates play an
important role in both creep and shrinkage. A well graded, coarser aggregate
with a low voids content decreases the effects of creep and shrinkage. Also,
hard, dense aggregates that are not absorptive and have a high modulus of
elasticity are desirable for low shrinkage and creep rates. Another important
aspect to reducing creep is the type of curing procedure performed prior to
loading. Very little creep occurs when a high-pressure steamed curing procedure
is used. Atmospheric and high-pressure steam curing produces little creep when
compared to the seven-day moist curing method. These two types of curing reduce
the drying shrinkage by half as much as they reduce creep. Other factors
affecting creep include type of cement, amount of cement paste, size and shape
of concrete, amount of reinforcement (rebar), volume-to-surface ratio,
temperature, and humidity
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Q. What
is bulking of sand?
ANSWER- Bulking of sand is a phenomenon in
which volume of sand increases due to wetness. It occurs because of sands
ability to incorporate moisture.
For instance, volume of sand
increases by 20-30% with addition of 5-8% moisture content. It happens due to
the formation of a thin film of water around sand grains. This thin film
interlocks a considerable amount of air between itself and the sand particle.
This interlocking and entrapping of air molecules increases the volume of sand
more than it is expected and hence called ‘bulking of sand’
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