# Fluid Mechanics Hydraulic Machinery Quiz

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# Fluid Mechanics Hydraulic Machinery Quiz

### Introduction

Hydraulics and fluid mechanics, or the study of liquids, is an important area for Mechanical Engineers. Whether designing a steam engine, or working on a pump or turbine, Mechanical Engineers need to know how the water or liquid is going to move or operate. Fluid Mechanics and Hydraulic Machinery is an important topic in Mechanical Engineering subjects.

Fluid Mechanics Hydraulic Machinery Quiz article, is exceedingly important for candidates preparing for RRB Junior Engineer Recruitment, SSC Junior Engineer Recruitment, GATE, UPSC (Civil services exam including IAS) and all Mechanical Engineering Exams in India. In this article, candidates can find different types of questions with solutions related to the Fluid Mechanics and Hydraulic Machinery topic. The article Fluid Mechanics Hydraulic Machinery Quiz, will assist the students in understanding the type of questions expected from the topic Fluid Mechanics and Hydraulic Machinery.

### Quiz

1. In Red wood viscometer

A. absolute value of viscosity is determined
B. part of the head of fluid is utilized in overcoming friction
C. fluid discharges through orifice with negligible velocity
D. comparison of viscosity is done.

Answer – Option D

2. Centre of buoyancy is

A. point of intersection of buoyant force and centre line of the body
B. centre of gravity of the body
C. centroid of displaced volume fluid
D. mid point between C.G. and metacentre.

Answer – Option C

3. Length of mercury column at a place at an altitude will vary with respect to that at ground in a

A. linear relation
B. hyperbolic relation
C. parabolic relation
D. manner first slowly and then steeply

Answer – Option D

4. When power is transmitted through a considerable distance by means of water under pressure,
the maximum power is transmitted when frictional loss of head is

A. one third of the total head supplied
B. half of the total head supplied

C. 10% of the total head
D. 17.7% of the total head.

Answer – Option A

5. A rota-meter is a device used to measure

A. velocity of fluid in pipes
B. velocity of gauges
C. vortex flow
D. flow of fluids

Answer – Option D

6. Reynolds number for pipe flow is given by

A. $$\frac{vD}{V}$$
B. $$\frac{vD \mu}{\delta}$$
C. $$\frac{vD \rho}{\mu}$$
D. $$\frac{vD}{\mu}$$

Answer – Option C

7. With rise in gas temperature, dynamic viscosity of most of the gases

A. increases
B. decreases
C. does not change significantly
D. none of these

Answer – Option A

8. The flow of water in a pipe of diameter 3000 mm can be measured by

A. Venturimeter
B. Rota-meter
C. Pilot tube
D. Orifice plate.

Answer – Option C

9. Which of the following is dimensionless parameter ?

A. Pressure coefficient
B. Froude number
C. Darcy Weisbach friction factor
D. None of these

Answer – Option D

10. A small plastic boat loaded with pieces of steel rods is floating in a bath tub. If the cargo is dumped into the water allowing the boat to float empty, the water level in the tub will

A. rise
B. fall
C. remains same
D. rise and then fall

Answer – Option B

11. Steady flow occurs when

A. pressure does not change along the flow
B. velocity does not change
C. conditions change gradually with time
D. conditions do not change with time at any point

Answer – Option D

12. A flow in which each liquid particle has a definite path and their paths do not cross each other, is called

A. Steady flow
B. Uniform flow
C. Streamline flow
D. Turbulent flow

Answer – Option C

13. Buoyant force is

A. resultant of upthrust and gravity forces acting on the body
B. resultant force on the body due to the fluid surrounding it
C. resultant of static weight of body and dynamic thrust of fluid
D. equal to the volume of liquid displaced by the body

Answer – Option D

14. In a rectangular notch, the ratio of percentage error in $$\frac{discharge}{measurement of head}$$ is

A. 1
B. $$\frac{1}{2}$$
C. $$\frac{3}{4}$$
D. $$\frac{3}{2}$$

Answer – Option D

15. Cavitation is caused by

A. high velocity
B. low barometric pressure
C. high pressure
D. low pressure

Answer – Option D

16. If the particles of a fluid attain such velocities that vary from point to point in magnitude and direction as well as from instant, the flow is

A. Uniform flow
B. Steady flow
C. Turbulent flow
D. Laminar flow

Answer – Option C

17. In a turbulent flow in a pipe

A. Reynolds number is greater than 10000
B. fluid particles move in straight lines
C. head loss varies linearly with flow rate
D. shear stress varies linearly with radius

Answer – Option D

18. The friction resistance in pipe is proportional to $${V}^{2}$$, according to

A. Froude-number
B. Reynolds-Weber
C. Darcy-Reynolds
D. Weber-Froude

Answer – Option A

19. In laminar flow, maximum velocity at the centre of pipe is how many times to the average velocity ?

A. 2
B. 3
C. 4
D. None of these

Answer – Option A

20. Pitot tube is used to measure the velocity head of

A. still fluid
B. laminar flow
C. turbulent flow
D. flowing fluid

Answer – Option D

1. In equilibrium condition, fluids are not able to sustain

A. shear force
B. resistance to viscosity
C. surface tension
D. geometric similitude

Answer – Option C

2. Flow occurring in a pipeline when a valve is being opened is

A. steady
B. unsteady
C. laminar
D. vortex

Answer – Option B

3. Total pressure on 1 m * 1 m gate immersed vertically at a depth of 2 m below the free water surface will be

A. 1000 kg
B. 2000 kg
C. 4000 kg
D. 8000 kg

Answer – Option A

4. The general equation of continuity for three dimensional flow of a compressible fluid for steady flow is

A. $$\frac{âˆ‚u}{âˆ‚x} + \frac{âˆ‚v}{âˆ‚y} + \frac{âˆ‚w}{âˆ‚z} = 0$$
B. $$\frac{âˆ‚u}{âˆ‚x} = \frac{âˆ‚v}{âˆ‚y} = \frac{âˆ‚w}{âˆ‚z} = 0$$
C. $$\frac{âˆ‚u}{âˆ‚x} + \frac{âˆ‚v}{âˆ‚y} + \frac{âˆ‚w}{âˆ‚z} = 1$$
D. $$\frac{âˆ‚u}{âˆ‚x} + \frac{âˆ‚v}{âˆ‚y} + \frac{âˆ‚w}{âˆ‚z} = u v w$$

where u, v and w are components of velocity in x, y and z directions respectively

Answer – Option A

5. A large Reynolds number is indication of

A. smooth and streamline flow
B. laminar flow
C. steady flow
D. highly turbulent flow

Answer – Option D

6. Non uniform flow occurs when

A. direction and magnitude of velocity at all points are identical
B. velocity of successive fluid particles, at any point, is same at successive periods of time
C. magnitude and direction of velocity do not change from point to point in the fluid
D. velocity, depth, pressure, etc. changes point to point in the fluid flow

Answer – Option D

7. In steady flow of a fluid, the acceleration of any fluid particle is

A. constant
B. variable
C. zero
D. never zero

Answer – Option C

8. For measuring flow by a venturimeter, it should be installed in

A. vertical line
B. horizontal line
C. inclined line with upward flow
D. in any direction and in any location

Answer – Option D

9. Fronde number is significant in

A. supersonic s, as with projectile and jet propulsion
B. full immersion or completely enclosed flow, as with pipes, aircraft’s wings, nozzles etc.,
C. simultaneous mot ion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect, as with shipâ€™s hulls
D. all of these

Answer – Option C

10. The fluid forces considered in the Navier Stokes equation are

A. gravity, pressure and viscous
B. gravity, pressure and turbulent
C. pressure, viscous and turbulent

D. gravity, viscous and turbulent

Answer – Option A

11. The depth of centre of pressure in rectangular lamina of height h with one side in the liquid
surface is at

A. h
B. $$\frac{h}{3}$$
C. $$\frac{2h}{3}$$
D. $$\frac{h}{2}$$

Answer – Option C

12. Reynolds number is significant in

A. supersonic s, as with projectile and jet propulsion
B. full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
C. simultaneous mot ion through two fluids where there is a surface of discontinuity,
gravity forces, and wave making effect, as with shipâ€™s hulls
D. all of these

Answer – Option B

13. Two dimensional flow occurs when the

A. directional and magnitude of the velocity at all points are identical
B. velocity of successive fluid particles, at any point, is same at successive periods of time
C. magnitude and direction of velocity do not change from point to point in the fluid
D. fluid particles move in a plane or parallel planes and the streamline patterns are identical in each plane

Answer – Option D

14. A streamline is defined as the line

A. parallel to central axis flow
B. parallel to outer surface to pipe
C. of equal velocity in a flow
D. along which the pressure drop is uniform

Answer – Option C

15. Match number is significant in

A. super sonics, as with projectiles and jet propulsion
B. full immersion or completely enclosed flow, as with pipes, aircraft’s wings, nozzles etc.
C. simultaneous motion through two fluids where there is a surface of discontinuity,
gravity force, and wave making effects, as with shipâ€™s hull
D. all of these

Answer – Option A

16. For an irrotational flow the equation $$\frac{{âˆ‚}^{2}\phi}{âˆ‚{x}^{2}} + \frac{{âˆ‚}^{2}\phi}{âˆ‚{y}^{2}}$$ is called

A. Bernoulliâ€™s equation
B. Cauchy Riemannâ€™s equation
C. Eulerâ€™s equation
D. Laplace equation.

Answer – Option D

17. Separation of flow occurs due to reduction of pressure gradient to

A. 0
B. negligibly low value
C. the extent such that vapor formation starts
D. none of these

Answer – Option C

18. The magnitude of water hammer depends on the

A. length of pipeline
B. speed at which the valve is closed
C. elastic properties of the liquid flowing through the pipe and pipe material
D. all of these

Answer – Option D

19. A cylinder is kept on a horizontal boundary past which an ideal fluid flows perpendicular to the cylinder axis. It will experience

A. no lift force
B. some lift force
C. lift force in vertically downward direction
D. lift force in vertically upward direction

Answer – Option A

20. When the water flows over a rectangular suppressed weir, the pressure beneath the
nappe is

A. very high
B. slightly above atmospheric
C. atmospheric
D. negative

Answer – Option D

1. The specific speed of a hydraulic turbine is given by

A. $$\frac{N\sqrt{P}}{{H}_{\frac{5}{4}}}$$
B. $$\frac{P\sqrt{N}}{{H}_{\frac{5}{4}}}$$
C. $$\frac{NP}{{H}_{\frac{3}{2}}}$$
D. $$\frac{\sqrt{NP}}{{H}_{\frac{3}{2}}}$$

Answer – Option A

2. For supplying feed water to a boiler which of the following pump is not used ?

A. Steam injector
B. Reciprocating pump
C. Multistage centrifugal pump
D. Gear pump

Answer – Option D

Explanation –

Boiler feed pump has to supply water at higher pressuresâ€“ more than the pressure of steam. Gear pumps are never used for such services.

3. In hydraulic coupling, as the ratio of the speed driven shaft to driving shaft increases, the efficiency

A. decreases
B. increases
C. remains constant
D. is independent of speed ratio

Answer – Option B

4. Pump selected for pumping sewage is

A. Reciprocating pump
B. Open impeller centrifugal pump
C. Multistage centrifugal pump
D. Screw pump

Answer – Option B

5. In a centrifugal pump when delivery valve is fully closed, the pressure of fluid inside the pump will

A. become zero
B. reduce
C. increase
D. remain unaltered

Answer – Option D

6. Undershot water wheels are those on which water acts

A. purely by impulse
B. partly by impulse and partly by reaction
C. purely by reaction
D. none of these

Answer – Option A

7. In the case of pelton turbine installed in a hydraulic power plant, the gross head available is
the vertical distance between

A. fore-bay and tail race
B. reservoir level and turbine inlet
C. fore-bay and turbine inlet
D. reservoir level and tail race

Answer – Option B

8. A hydraulic coupling belongs to the category of

A. power absorbing machines
B. power developing machines
C. energy generating machines
D. energy transfer machines

Answer – Option D

Explanation –

A hydraulic coupling consists of a pump unit fitted on the driving shaft and a turbine unit on to the driven shaft. These two units are housed in a common casing in such a manner that output of the pump is fed to the turbine unit which rotates and drives the driven shaft. The medium fluid used is generally oil.

9. For pumping molasses, it is preferable to employ

A. reciprocating pump
B. centrifugal pump with double shrouds
C. open impeller pump
D. multistage centrifugal pump

Answer – Option C

Explanation –

Molasses is highly viscous therefore open impeller should be used. Normally a screw pump is used for pumping highly viscous fluids.

10. In the case of a centrifugal pump, cavitation will occur if

A. it operates above the minimum net positive suction head
B. it operates below the minimum net positive suction head
C. the pressure at the inlet of the pump is above the atmospheric pressure
D. the pressure at the inlet of the pump is equal to the atmospheric pressure

Answer – Option D

11.The hydraulic radius is given by

A. wetted perimeter divided by area
B. area divided by square of wetted perimeter
C. square root of area
D. area divided by wetted perimeter

Answer – Option D

12.Specific speed (metric) = k Ã— specific (FPS), where k has the value of

A. 1
B. 1.75
C. 2.37
D. 0.67

Answer – Option D

13. The cavitation and pitting can be prevented by creating which one of the following conditions?

A. Reducing the pressure head
B. Reducing the velocity head
C. Increasing the elevation head
D. Reducing the piezometric head

Answer – Option D

14.Pressure rise due to water hammer in a pen-stock depends on

A. water level in the reservoir, and elasticity of water
B. density of water
C. roughness of pipe
D. all of these

Answer – Option D

15.A pumped storage plant is a

A. high head plant
B. run-off river plant
C. peak load plant
D. base load plant

Answer – Option A

16.Which of the following statements about gear pumps are true?

I. Gear pumps are best suited for high pressures and small discharges.
II. Gear pumps are self priming.
III.Efficiency of a gear pump depends on the slip.
IV. The discharge is inversely proportional to the axial length of the gear tooth.

A. I and IV only
B. II and III only
C. III and I only
D. II and IV only

Answer – Option B

17. In the figure below, which curve represents the condition for backward curved vanes in a
centrifugal pump?

A. Curve A
B. Curve B
C. Curve C
D. Curve D

Answer – Option C

18.In all reaction turbines, maximum efficiency is obtained, if

A. guide vane angle is 90Â°
B. blade angle of the runners is 90Â° at the inlet
C. blade angle of the runners is 90Â° at the outlet
D. angle of the absolute velocity vector at the outlet is 90Â°

Answer – Option D

Explanation –

In case of reaction turbines, maximum efficiency is obtained when absolute velocity vector at the
outlet is 90Â°

19. The shut off head will be nearly

A. 0
B. 18.0 m
C. 25.5 m
D. 35 m

Answer – Option D

Explanation –

By extrapolating Q vs H curve, the shut off head which is corresponding to Q = 0 is 35.5 m.

20.Double hemispherical buckets are used in

A. Kaplan turbine
B. Francis turbine
C. Propeller turbine
D. Pelton wheel

Answer – Option D

Explanation –

Buckets are double hemispherical in shape. These buckets are made of cast iron, bronze or stainless
steel.

1. A reciprocating pump

A. requires priming
B. requires air vessel
C. requires high operating speeds
D. is used for viscous fluids only

Answer – Option B

Explanation –

A reciprocating pump is self priming. It operates at low speeds. It is not suitable for viscous liquids, paper pulp, molasses, etc.

2. Air vessel in a reciprocating pump is used to

A. obtain continuous supply of water at uniform rate
B. increase delivery
C. reduce suction head
D. remove any entrapped air from water

Answer – Option A

Explanation –

Air vessel smooth-ens water discharge which is otherwise pulsating. Air vessel may be fitted on suction side and/or delivery side.

3. A tapered draft tube as compared to a cylindrical draft tube

A. prevents hammer blow and surges
B. responds better to load functions
C. converts more of kinetic head into pressure head
D. prevents cavitation even under reduced discharges

Answer – Option C

Explanation –

A tapered draft tube is used for low specific speed vertical shaft turbines. Its maximum cone angle
is 8Â°. If angle is more than this, water does not touch the inner walls, causing vertices and loss of head. Maximum efficiency obtained in this tube is 9%. The tube must discharge sufficiently below the tail water level.

4. The specific speeds of radial vane pump, mixed flow pump and axial flow pump are $${NS}_{1}$$, $${NS}_{2}$$ and $${NS}_{3}$$ respectively. Then

A. $${NS}_{1} > {NS}_{2} >{NS}_{3}$$
B. $${NS}_{3} > {NS}_{2} >{NS}_{1}$$
C. $${NS}_{2} > {NS}_{3} >{NS}_{1}$$
D. $${NS}_{3} > {NS}_{1} >{NS}_{2}$$

Answer – Option B

5. Centrifugal pumps operating in series will result in

A. higher discharge
B. reduced power consumption
C. higher head
D. low speed operation

Answer – Option C

Explanation –

Series operation is achieved by having one pump discharge into he suction of the next . This
arrangement is used primarily to increase the discharge head.

6.Jet pumps are often used in process industry for their

A. high efficiency
B. easy maintenance
C. large capacity
D. capacity to transport gases, liquids and mixtures of both

Answer – Option B, D

7.Spouting velocity is

A. ideal velocity of jet
B. 50% of ideal velocity of jet
C. actual velocity of jet
D. velocity of jet under some specified conditions

Answer – Option A

8. The comparison between pumps operating in series and in parallel is

A. Pumps operating in series boost the discharge, whereas pumps operating in parallel boost the head.
B. Pumps operating in parallel boost the discharge, whereas pumps operating in series
boost the head
C. In both cases there would be a boost in discharge only.
D. In both cases there would be a boost in head only.

Answer – Option B

9.A pelton turbine is considered suitable for which of the following head ?

A. 10 to 12 metres
B. 20 to 30 metres
C. 35 to 50 metres
D. 100 to 250 metres

Answer – Option D

Explanation –

By extrapolating Q vs H curve, the shut off head which is corresponding to Q = 0 is 35.5 m.

10.Material for water turbine should have

A. high creep resistance
B. high temperature resistance
C. high corrosion resistance
D. low ductility

Answer – Option C

11. The coefficient of discharge ( $${C}_{D}$$) of an orifice varies with

A. Reynolds number
B. Weber number
C. Froude number
D. Mach number

Answer – Option A

12. The shear stress distribution for a fluid flowing in between the parallel plates, both at rest, is

A. constant over the cross-section
B. maximum at the mid-plane and varies linearly with distance from mid-plane
C. zero at the mid-point and varies linearly with distance from mid-plane
D. zero at the plates and varies exponentially to mid-point

Answer – Option C

13. Friction drag is generally larger than the pressure drag in

A. flow past a sphere
B. flow past a cylinder
C. flow past an airfoil
D. flow past a thin sheet

Answer – Option B

14. Capillarity is due to

A. Cohension
B. Adhesion
C. Adhesion and cohesion
D. Gravity

Answer – Option C

15. Principle of similitude forms the basis of

A. comparing two identical equipment
B. designing models so that the result can be converted to prototypes
C. comparing similar ly between design and actual equipment
D. hydraulic design

Answer – Option B

16. If V is the mean velocity of flow, then according to Darcy-Weisbach equation for pipe flow, energy loss over a length of pipe is proportional

A. V
B. $$\frac{1}{V}$$
C. $${V}^{2}$$
D. $$\sqrt{V}$$

Answer – Option B

17. Head loss in turbulent flow in a pipe

A. varies directly as velocity
B. varies inversely as square of velocity
C. varies approximately as square of velocity
D. varies inversely as velocity.

Answer – Option D

18. The horizontal component of force on a curved surface is equal to the

A. product of pressure at its centroid and area
B. weight of liquid retained by the curved area
C. force on a vertical projection of the curved surface
D. weight of liquid vertically above the curved surface

Answer – Option C

19. Total pressure on the top of a closed cylindrical vessel of radius r filled with liquid is
proportional to

A. r
B. $$\frac{1}{r}$$
C. $$\frac{1}{{r}^{2}}$$
D. $${r}^{2}$$

Answer – Option D

20. The drag coefficient for laminar flow varies as (where Re = Reynolds number)

A. Re
B. $${r}^{-1}$$
C. $${r}^{\frac{1}{2}}$$
D. $${r}^{- \frac{1}{2}}$$

Answer – Option D

1. If one of the walls moves in the direction of flow with uniform velocity while the other wall is stationary, then the resulting flow between parallel walls is called

A. Plug flow
B. Stokeâ€™s flow
C. Couette flow
D. Eulerâ€™s flow

Answer – Option A

2. In series-pipe applications

A. head loss through each pipe added to obtain the total head loss
B. head loss is same through each pipe
C. friction factor is assumed for each pipe
D. flow increases

Answer – Option D

3. For pipe flow, at constant diameter, capacity is proportional to

A. $$\sqrt{head}$$
B. head
C. $${head}^{\frac{3}{2}}$$
D. $${head}^{2}$$

Answer – Option C

4. The velocity distribution for flow between two fixed parallel plates

A. is constant over the cross-section
B. is zero at the plates and increases linearly to the mid plane
C. varies parabolic-ally across the section
D. is zero in middle and increase linearly towards the plates

Answer – Option A

5. The most economical section of a rectangular channel for maximum discharge is obtained when
its depth is equal to

A. half the breadth
B. twice the breadth
C. same as the breadth
D. one third the breadth.

Answer – Option C

6. Region downstream from the streamline where separation takes place from the boundary is
known as

A. wake
B. lift
C. drag
D. cavitation

Answer – Option D

7. A low pressure of the order of $${10}^{-10}$$ torr can be measured in a chamber with

A. Manometer
B. Bourdon vacuum gauge
C. Pirani gauge
D. Ionization chamber

Answer – Option A

8. To avoid a correction for the effect of capillarity in manometers, diameter of tube should be

A. less than 1 mm
B. less than 3 mm
C. less than 4.5 mm
D. all of these

Answer – Option D

9. The river flow during floods can be classified as

A. steady uniform flow
B. unsteady uniform flow
C. steady non-uniform flow
D. unsteady non-uniform flow

Answer – Option D

10. Wake always occurs

A. before a separation point
B. after a separation point
C. before and after a separation point
D. none of these

Answer – Option B

11. In a flow field, at the stagnation point

A. pressure is zero
B. total energy is zero
C. pressure head is equal to velocity
D. all the velocity head is converted into pressure head.

Answer – Option B

12. Total drag on a body is the sum of

A. pressure drag and velocity drag
B. friction drag and velocity drag
C. friction drag and pressure drag
D. pressure drag, velocity drag and friction drag.

Answer – Option C

13. Specific speed of a pump and specific speed of a turbine are (symbols have the usual meaning)

A. $$\frac{N\sqrt{Q}}{{H}_{\frac{3}{4}}} and \frac{N\sqrt{P}}{{H}_{\frac{5}{4}}}$$ respectively
B. $$\frac{N\sqrt{Q}}{{H}_{\frac{3}{4}}} and \frac{N\sqrt{P}}{{H}_{\frac{3}{4}}}$$ respectively
C. $$\frac{N\sqrt{Q}}{{H}_{\frac{5}{4}}} and \frac{N\sqrt{P}}{{H}_{\frac{5}{4}}}$$ respectively
D. $$\frac{N\sqrt{Q}}{{H}_{\frac{2}{4}}} and \frac{N\sqrt{P}}{{H}_{\frac{5}{4}}}$$ respectively

Answer – Option A

14. One horse power is equal to

A. 102 watts
B. 75 watts
C. 550 watts
D. 735 watts

Answer – Option D

15. Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of

A. high initial and maintenance cost
B. lower discharge
C. lower speed of operation
D. necessity of air vessel

Answer – Option A

16. The maximum continuous power available from a hydroelectric plant under most adverse
hydraulic conditions, is called

A. Base power
B. Firm power
C. Primary power
D. Unpredictable

Answer – Option B

17. The movable wicket gates of a reaction turbine are used to

A. control the flow of water passing through the turbine
B. control the pressure under which the turbine is working
C. strengthen the casing of the turbine
D. reduce the size of the turbine

Answer – Option B

18. A Fourneyron turbine is

A. outward flow reaction turbine
B. inward flow reaction turbine
C. outward flow impulse turbine
D. inward flow impulse turbine

Answer – Option A

19. The degree of reaction of a turbine is defined as the ratio of

A. static pressure drop to total energy transfer
B. total energy transfer to static pressure drop
C. change of velocity energy across the turbine to the total energy transfer
D. velocity energy to pressure energy

Answer – Option A

20. In a centrifugal pump installation while starting, the position of delivery valve is

A. fully open
B. fully closed
C. half open
D. more than half open

Answer – Option B

1. For attaining a non-overloading characteristic in centrifugal pumps

A. backward bent vanes are preferred over forward bent vanes
B. forward bent vanes are preferred over backward bent vanes
C. forward bent vanes are preferred over vanes radial at outlet
D. vanes radial at outlet are prefer red over backward vanes

Answer – Option A

2. Which one of the following statements regarding reciprocating pumps is correct ?

A. Friction head is mainly responsible for causing cavitation in a reciprocating pump at the beginning of the suction stroke.
B. Effect of acceleration pressure on reciprocating pumps appears parabolic and has
the maximum effect at the middle of the delivery stroke.
C. Air vessel reduces the acceleration head and consequently reduces the effect of friction head also
D. The maximum permissible suction lift in a double acting reciprocating pumpis independent of vapour pressure.

Answer – Option C

3. On an immersed body in a flowing fluid the lift force is

A. due to buoyant force.
B. always in the opposite direction to gravity
C. due to wake phenomenon
D. the dynamic fluid-force component normal to approach velocity

Answer – Option B

4. A plot between power generated in MW and time is known as

A. Load curve
B. Load duration curve
C. Load factor
D. Demand curve

Answer – Option A

5. A centrifugal pump takes too much power, due to

A. low speed
B. air in water
C. air leakage
D. heavy liquid

Answer – Option B

6. In reaction turbine the draft tube is used to

A. transport water to downstream without eddies
B. reconvert kinetic energy to flow energy by a gradual expansion of the flow cross-section
C. increase the effective head
D. prevent air from entering

Answer – Option B

7. A drum of radius R full of a fluid of density d is rotated at $$\omega$$ rad/sec. The increase in pressure at the outer edge of the drum will be

A. $$\frac{{\omega}^{2}{R}^{2}d}{2}$$
B. $$\frac{{\omega}^{2}R d}{2}$$
C. $$\frac{\omega R d}{2}$$
D. $$\frac{\omega{d}^{2} R}{2}$$

Answer – Option A

8. In axial flow turbines, water enters

A. radially but leaves axially
B. axially but leaves radially
C. at an angle but leaves axially
D. axially and leaves axially

Answer – Option A

9. When pressure p, flow rate Q, diameter D, and density d, a dimensionless group is represented by

A. $$\frac{P {Q}^{2}}{d {D}^{4}}$$
B. $$\frac{P}{d {D}^{4}{Q}^{2}}$$
C. $$\frac{P {D}^{4}}{d {q}^{2}}$$
D. $$\frac{P {D}^{4}}{d {D}^{2}}$$

Answer – Option A

10. Viscosity is the most important property in the

A. travel of a bullet through air
B. water jet issuing from a fire air
C. formation of soap bubbles
D. flow of castor oil through a tube.

Answer – Option C

11. A type of flow in which the fluid particles while moving in the direction of flow rotate about their mass centre, is known as

A. steady flow
B. uniform flow
C. laminar flow
D. rotational flow

Answer – Option C

12. If pressure at any point in the liquid approaches the vapor pressure, liquid starts vaporizing and creates pockets or bubbles of dissolved gases and vapors. This phenomenon is

A. surface tension
B. adhesion
C. vaporization
D. cavitation

Answer – Option A

13. Fire hose nozzle is generally made of

A. divergent shape
B. convergent shape
C. cylindrical shape
D. parabolic shape

Answer – Option C

14. Discharge of broad crested weir is maximum in the head of water on downstream side of weir as compared to head on the upstream side of the weir is

A. one-half
B. one-third
C. two-third
D. three-fourth

Answer – Option D

15. For small discharge at high pressure, pump preferred is

A. centrifugal
B. axial flow
C. propeller
D. reciprocating

Answer – Option D

16. Discharge over a sharp-edged rectangular notch of width w and depth h is equal to

A. $$\frac{2}{3}{C}_{d} w \sqrt{{2gh}^{\frac{5}{2}}}$$
B. $$\frac{2}{3}{C}_{d} w \sqrt{2gh}$$
C. $$\frac{2}{3}{C}_{d} w \sqrt{{2gh}^{\frac{3}{2}}}$$
D. $$\frac{8}{15}{C}_{d} w \sqrt{{2gh}^{\frac{3}{2}}}$$

Answer – Option C

17. In a free vortex motion, tangential velocity of the water particles is proportional to

A. r
B. $${r}^{2}$$
C. $$\frac{1}{r}$$
D. $$\frac{1}{{r}^{2}}$$

where, r = distance from the centre.

Answer – Option C

18. To replace a pipe of diameter D by n parallel pipes of diameter d, the formula used is

A. $$d = \frac{D}{n}$$
B. $$d = \frac{D}{{n}^{\frac{1}{2}}}$$
C. $$\frac{D}{{n}^{\frac{3}{2}}}$$
D. $$\frac{D}{{n}^{\frac{2}{5}}}$$

Answer – Option D

19. Vertical component of pressure force on a submerged curve surface is equal to

A. weight of liquid vertically above the curved surface and extending upon the free surface
B. force on a vertical projection of the curved surface
C. product of pressure at centro-id and surface area
D. horizontal component

Answer – Option A

20. The fluid forces considered in the Navier-Stokes equation are

A. gravity velocity and viscous
B. gravity, pressure and turbulent
C. pressure, viscous and turbulent
D. gravity, viscous and turbulent

Answer – Option A

21. For a flow to be rotational, velocity normal to the plane of area should be equal to the

A. angular velocity vector
B. half the angular velocity vector
C. twice the angular velocity vector
D. zero

Answer – Option C

22. Continuity equation for an in compressible fluid is

A. $${A}_{1}{V}_{1} = {A}_{2} {V}_{2}$$
B. $${A}_{1}{V}_{1} {\rho}_{1} = {A}_{2} {V}_{2} {\rho}_{2}$$
C. $$\frac{{A}_{1}{V}_{1}}{{\rho}_{1}} = \frac{{A}_{2}{V}_{2}}{{\rho}_{2}}$$
D. $$\frac{{A}_{1}{\rho}_{1}}{{V}_{1}} = \frac{{A}_{2}{\rho}_{2}}{{V}_{2}}$$

where V = velocity, $$\rho$$= density and A = area

Answer – Option A

23. Loss of head due to friction in a pipe of uniform diameter with viscous flow is equal to

A. Reynolds number (Re)
B. $$\frac{1}{Re}$$
C. $$\frac{4}{Re}$$
D. $$\frac{16}{Re}$$

Answer – Option D

24. Hydraulic grade line for any flow system as compared to energy line is

A. above
B. below
C. at same level
D. uncertain

Answer – Option B

25. The effect of negative pressure beneath the nappe in case of flow of wat er over a r ect angular suppressed weir is to

A. decrease the discharge
B. increase the discharge
C. increase frictional resistance
D. reduce frictional resistance

Answer – Option B

1. Gradually varied flow is

A. steady uniform flow
B. steady non-uniform flow
C. unsteady uniform flow
D. unsteady non-uniform flow

Answer – Option B

2. A fluid in which resistance to deformation is independent of the shear stress, is known as

A. Bingham plastic fluid
B. Pseudo plastic fluid
C. Dilatant fluid
D. Newtonian fluid

Answer – Option D

3. Pressure drag results from

A. skin-friction
B. deformation drag
C. development of a stagnation point
D. occurrence of a wake

Answer – Option D

4. Turbulent flow is hydraulically smooth if ratio $$\frac{height of roughness projection}{thickness of laminar sub – layer}$$ is less than

A. 1.00
B. 0.75
C. 0.50
D. 0.25

Answer – Option D

5. Bluff body surface

A. is smooth so that friction can be neglected
B. coincides with streamlines
C. does not coincide with streamlines
D. perpendicular to streamlines

Answer – Option C

6. Centre of pressure on an inclined plane is

A. at the centro-id
B. above the centro-id
C. below the centro-id
D. at metacentre

Answer – Option C

7. Separation of flow occurs when pressure gradient

A. tends to approach zero
B. becomes negative
C. changes abruptly
D. reduces to a value when vapor formation starts

Answer – Option C

8. The friction head lost due to flow of a viscous fluids through a circular pipe of length L and diameter d with a velocity v, and pipe friction factor â€˜fâ€™ is

A. $$\frac{4fL}{d} .\frac{{v}^{2}}{2g}$$
B. $$\frac{4fL}{\pi {d}^{2}} .\frac{{v}^{2}}{2g}$$
C. $$\frac{{v}^{2}}{2g}$$
D. $$\frac{4fL}{\pi d} .\frac{{v}^{2}}{2g}$$

Answer – Option A

9. The rate of change of linear momentum is equals to

A. active force
B. reactive force
C. torque
D. work done

Answer – Option C

10. Component of the force of fluid on the body (which is generally inclined to the direction of motion of the body) parallel to the direction of motion is called

A. drag
B. life
C. wake
D. thrust

Answer – Option A

11. Energy loss in flow through nozzle as compared to venturimeter is

A. same
B. more
C. less
D. unpredictable

Answer – Option A

12. The rate of change of moment of momentum represents the

A. force exerted by fluid
B. torque applied by the fluid
C. work done by the fluid
D. power developed by the fluid

Answer – Option B

13. If the characteristics of a pump are as shown in the figure, then abscissa represents

A. head
B. RPM
C. discharge
D. power

Answer – Option C

14. To obtain relation for the specific speed, the assumption made is that all pumps

A. are similar
B. of a given type are similar
C. of a given type are geometrically similar
D. are hydraulically similar

Answer – Option C

15. Water turbines may be put in the decreasing order of specific speed as

A. Propeller turbine, Reaction turbine, Impulse turbine
B. Pelton wheel, Francis turbine, Kaplan turbine
C. Reaction turbine, Impulse turbine, Propeller turbine
D. Propeller turbine, Impulse turbine, Reaction turbine

Answer – Option A

16. Mixed flow turbines are

A. radial inward flow type
B. radial outward flow type
C. partly radial partly axial
D. parallel flow type

Answer – Option C

17. A foot valve is provided on

A. Centrifugal pumps
B. Kaplan turbines
C. Pelton wheels
D. All of these

Answer – Option A

18. Which one is different from the others ?

A. Axial flow impeller
B. Mixed flow impeller
C. Warped vane impeller
D. Shrouded impeller

Answer – Option D

19. In a reaction turbine

A. it is possible to regulate the flow without loss
B. it must be placed at the foot of the fall and above the tail race
C. work done is purely by the change in the kinetic energy of jet
D. only part of the head is converted into velocity before water enters the wheel

Answer – Option D

20. The discharge through a rectangular weir varies as

A. H
B. $${H}^{\frac {1}{2}}$$
C. $${H}^{2}$$
D. $${H}^{\frac {5}{2}}$$

Answer – Option D

21. The hydraulic gradient line is always

A. below the total energy line
B. parallel to the bottom
C. above the total energy line
D. none of these

Answer – Option A

22. In in-volute casing the velocity of water

A. decreases but pressure increases
B. and pressure both increase
C. and pressure both decrease
D. increases but pressure decreases

Answer – Option A

23. The pump which is different from others is

A. Simplex pump
B. Plunger pump
C. Piston pump
D. Centrifugal pump

Answer – Option D

24. If a centrifugal pump is noisy in operation, it may be due to

A. faulty priming
B. suction head too high
C. air in water
D. mechanical defect

Answer – Option D

25. Francis turbine is best suited for

A. medium head application from 24 to 180 m
B. high head installation above 180 m
C. low head installation up to 30 m
D. all types of heads

Answer – Option A

1. Hydraulic accumulator is used for

A. accumulating oil
B. supplying large quantities of oil for very short duration
C. supplying energy when main supply fails
D. accumulating hydraulic energy

Answer – Option C

2. Run away speed of a hydraulic turbine is the speed

A. at full load
B. at which turbine runner will be damaged
C. at which the turbine runner is allowed to revolve freely without load and with the
wicket gates wide open
D. corresponding to maximum overload permissible

Answer – Option C

3. According to the laws of proportionality for homologous turbines, speed is proportional to

A. $$\frac{\sqrt{H}}{D}$$
B. $$\sqrt{\frac{H}{D}}$$
C. $$\frac{\sqrt{H}}{{D}^{2}}$$
D. $$\sqrt{HD}$$

Answer – Option A

4. A hydraulic intensifier normally consists of

A. two cylinders, two rams and a storage device
B. a cylinder and a ram
C. two co-axial rams and two cylinders
D. a cylinder, a piston, storage tank and control valve

Answer – Option C

5. According to the laws of proportionality for homologous turbines, discharge is proportional to

A. $$D \sqrt{H}$$
B. $${D}^{2} \sqrt{H}$$
C. $${D}^{2}{D}^{\frac {3}{2}}$$
D. $${D}^{2} H$$
E.

Answer – Option B

6. Any change in load is adjusted by adjusting on turbine

A. net head
B. absolute velocity
C. blade velocity
D. flow

Answer – Option D

7. For pumping viscous oil, pump used will be

A. centrifugal pump
B. reciprocating pump
C. turbine pump
D. screw pump

Answer – Option D

8. The cavitation in reaction type hydraulic turbines is avoided by

A. using highly polished blade
B. using stainless steel runner
C. installing the turbine below the tail race level
D. all of the above

Answer – Option D

9. Propeller turbine is best suited for

A. medium head application from 20 to 180 m
B. low head installation up to 30 m
C. high head installation above 180 m
D. all types of heads

Answer – Option B

10. A hydraulic jump can occur under all of the following conditions except :

A. on the upstream side of the sluices
B. at the foot of the spillways
C. where the gradient suddenly changes from a steep slope to a flat slope
D. when water moving in shooting flow impacts with water having a larger depth with
streaming flow

Answer – Option A

11. As per the aerofoil theory of Kaplan turbine blade design, guide angle is as the angle between

A. lift and resultant force
B. drag and resultant force
C. lift and tangential force
D. lift and drag

Answer – Option A

12. Power required to drive a centrifugal pump is proportional to (D = impeller diameter)

A. D
B. $${D}^{2}$$
C. $${D}^{3}$$
D. $${D}^{4}$$

Answer – Option D

13. Ratio of maximum load to rated plant capacity is known as

A. Load factor
B. Utilization factor
C. Maximum load factor
D. Capacity factor

Answer – Option B

14. A double acting reciprocating pump compared to single acting pump will have nearly

A. double efficiency
B. double head
C. double flow
D. double weight

Answer – Option C

15. For centrifugal pump

A. $$head \propto{speed}^{2}$$
B. $$power \propto{speed}^{3}$$
C. $$head \propto{diameter}^{2}$$
D. none of these

Answer – Option A