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Mechanical Engineering : Hydraulic Machines - Quiz(MCQ)
1 .
Hydraulic energy is converted into another form of energy by hydraulic machines. What form of energy is that?
A)
Mechanical Energy
B)
Elastic Energy
C)
Nuclear Energy
D)
Electrical Energy

Correct Answer :   Mechanical Energy

Explanation : Hydraulic machines firstly convert the energy possessed by water into mechanical energy. Later it can be transformed into electrical energy.

2 .
Which principle is used in Hydraulic Turbines?
A)
Braggs law
B)
Faraday law
C)
Charles law
D)
Newton’s second law

Correct Answer :   Newton’s second law

Explanation : A Hydraulic Machine uses the principle of momentum which states that a force is generated which is utilized in a turbine.

3 .
Buckets and blades used in a turbine are used to:
A)
Switch off the turbine
B)
To regenerate the power
C)
Alter the direction of water
D)
To regulate the wind speed

Correct Answer :   Alter the direction of water

Explanation : Turbines use blades and buckets to alter the direction of water. It is used to change the momentum of water. As momentum changes, force is produced to rotate the shaft of a hydraulic machine.

4 .
The cavitation in a hydraulic machine is mainly due to
A)
low velocity
B)
high velocity
C)
low pressure
D)
high pressure

Correct Answer :   low pressure

5 .
The unit speed of the turbine runner is
A)
N/H
B)
N/√H
C)
N/H²
D)
N/H³

Correct Answer :   N/√H

6 .
In a centrifugal pump, the regulating valve is provided on the
A)
impeller
B)
casing
C)
suction pipe
D)
delivery pipe

Correct Answer :   delivery pipe

7 .
A Francis turbine is an outward flow reaction turbine.
A)
True
B)
False
C)
Can Not Say
D)
None of the above

Correct Answer :   False

8 .
Power required to drive a centrifugal pump is __________ proportional to N3.
A)
directly
B)
inversely
C)
Can Not Say
D)
None of the above

Correct Answer :   directly

9 .
The force exerted (in newton) by a jetof water impinging normally on a fixed plate is (where w = Specific weight of water in N/m³, a = Cross-sectional area of jet in m², and V = Velocity of jet in m/s)
A)
waV/g
B)
waV/2g
C)
waV²/g
D)
waV²/2g

Correct Answer :   waV²/g

10 .
The unit power developed by a turbine is (where P = Power developed by the turbine under a head of water (H))
A)
P/√H
B)
P/H
C)
P/H2
D)
P/H3/2

Correct Answer :   P/H3/2

11 .
Delivery head of a centrifugal pump is
A)
directly proportional to N
B)
inversely proportional to N
C)
directly proportional to N²
D)
inversely proportional to N²

Correct Answer :   directly proportional to N²

12 .
A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit discharge of wheel is
A)
0.25 m³/s
B)
0.5 m³/s
C)
1.5 m³/s
D)
2.5 m³/s

Correct Answer :   0.25 m³/s

13 .
The power developed by a turbine is (where H = Head of water under which the turbine is working)
A)
directly proportional to H1/2
B)
directly proportional to H3/2
C)
inversely proportional to H1/2
D)
inversely proportional to H3/2

Correct Answer :   directly proportional to H3/2

14 .
Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.
A)
diameter
B)
cube of diameter
C)
fourth power of diameter
D)
square of diameter

Correct Answer :   fourth power of diameter

15 .
The mechanical efficiency of an impulse turbine is
A)
ratio of the Work done on the wheel to the energy of the jet
B)
ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
C)
Both (A) and (B)
D)
ratio of the actual work available at the turbine to the energy imparted to the wheel

Correct Answer :   ratio of the actual work available at the turbine to the energy imparted to the wheel

16 .
The overshot water wheels are those in which the wheel runs entirely by the __________ of water.
A)
weight
B)
impulse
C)
Can Not Say
D)
None of the above

Correct Answer :   weight

17 .
If Hg is the gross or total head and hf is the head lost due to friction, then net or effective head (H) is given by
A)
H = Hg - hf
B)
H = Hg/hf
C)
H = Hg x hf
D)
H = Hg + hf

Correct Answer :   H = Hg - hf

18 .
In a Kaplan turbine runner, the number of blades are generally between
A)
2 to 4
B)
4 to 8
C)
8 to l6
D)
16 to 24

Correct Answer :   4 to 8

19 .
Discharge of a centrifugal pump is
A)
directly proportional to diameter of its impeller
B)
inversely proportional to diameter of its impeller
C)
directly proportional to (diameter)² of its impeller
D)
inversely proportional to (diameter)² of its impeller

Correct Answer :   directly proportional to (diameter)² of its impeller

Explanation : Discharge of a centrifugal pump is directly proportional to (Diameter)^2 of its impeller.

Head of a centrifugal pump is directly proportional to (Diameter)^2 of its impeller.

Power Developed of a centrifugal pump is directly proportional to (Diameter)^4 of its impeller.

20 .
The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which
A)
develops unit power under unit head
B)
develops unit power under unit speed
C)
delivers unit discharge under unit head
D)
delivers unit discharge under unit speed

Correct Answer :   develops unit power under unit head

21 .
If the net positive suction head (NPSH) requirement for the pump is not satisfied, then
A)
efficiency will be low
B)
no flow will take place
C)
cavitation will be formed
D)
excessive power will be consumed

Correct Answer :   cavitation will be formed

22 .
The runaway speed of a hydraulic turbine is the speed
A)
at full load
B)
corresponding to maximum overload permissible
C)
at which there will be no damage to the runner
D)
at which the turbine will run freely without load

Correct Answer :   at which the turbine will run freely without load

23 .
The type of centrifugal pump preferred for a specific speed of 20 r.p.m. is
A)
high speed pump with radial flow at outlet
B)
slow speed pump with radial flow at outlet
C)
high speed pump with axial flow at outlet
D)
medium speed pump with radial flow at outlet

Correct Answer :   slow speed pump with radial flow at outlet

24 .
The cavitation in a hydraulic machine
A)
reduces the discharge of a turbine
B)
causes noise and vibration of various parts
C)
causes sudden drop in power output and efficiency
D)
All of the above

Correct Answer :   All of the above

25 .
A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is __________ of the jet velocity
A)
one-half
B)
one-third
C)
two-third
D)
three-fourth

Correct Answer :   one-third

26 .
A turbine develops 10000 kW under a head of 25 metres at 135 r.p.m. Its specific speed is
A)
175.4 r.p.m.
B)
215.5 r.p.m.
C)
241.5 r.p.m.
D)
275.4 r.p.m

Correct Answer :   241.5 r.p.m.

27 .
The power of a centrifugal pump working under constant head and discharge increases with the speed.
A)
True
B)
False
C)
Can Not Say
D)
None of the above

Correct Answer :   True

28 .
Which of the following is not a reaction turbine?
A)
Jonval turbine
B)
Furneyron turbine
C)
Pelton wheel
D)
Thomson's turbine

Correct Answer :   Pelton wheel

29 .
Which of the following pump is successfully used for lifting water to the turbines?
A)
Air lift pump
B)
Centrifugal pump
C)
Reciprocating pump
D)
Jet pump

Correct Answer :   Jet pump

30 .
___________is the electric power obtained from the energy of the water.
A)
Nuclear power
B)
Hydroelectric power
C)
Thermal power
D)
Roto dynamic power

Correct Answer :   Hydroelectric power

Explanation : The energy from the energy of water is also called hydro power. The electric power so obtained is known as hydroelectric power.

31 .
Which energy generated in a turbine is used to run electric power generator linked to the turbine shaft?
A)
Elastic Energy
B)
Mechanical Energy
C)
Kinetic Energy
D)
Potential Energy

Correct Answer :   Mechanical Energy

Explanation : The kinetic and potential energies produced are converted to some useful mechanical energy. This part of energy is available to the turbine shaft.

32 .
Which kind of turbine is a Fourneyron Turbine?
A)
Outward flow turbine
B)
Mixed flow turbine
C)
Inward flow turbine
D)
Radial flow turbine

Correct Answer :   Outward flow turbine

Explanation : In a Fourneyron turbine, the flow is centrifugal type. The flow is outwards from the centre to the periphery.

33 .
How many types of Reaction turbines are there?
A)
7
B)
6
C)
5
D)
4

Correct Answer :   5

Explanation : There are five types of reaction turbines namely VLH, Francis, Kaplan, Tyson, Gorolov helical turbine.

34 .
The function of guide vanes in a reaction turbine is to
A)
allow the water to enter the runner without shock
B)
allow the water to flow over them, without forming eddies
C)
allow the required quantity of water to enter the turbine
D)
All of the above

Correct Answer :   All of the above

35 .
Mechanical efficiency of a centrifugal pump is the ratio of
A)
energy supplied to the pump to the energy available at the impeller
B)
manometric head to the energy supplied by the impeller per kN of water
C)
energy available at the impeller to the energy supplied to the pump by the prime mover
D)
actual workdone by the pump to the energy supplied to the pump by the prime mover

Correct Answer :   energy available at the impeller to the energy supplied to the pump by the prime mover

36 .
If the ratio of corresponding velocities at corresponding points are equal, then the model and the prototype are said to have dynamic similarity.
A)
Correct
B)
Incorrect
C)
Can Not Say
D)
None of the above

Correct Answer :   Incorrect

37 .
Which of the following statement is correct ?
A)
In an impulse turbine, the water impinges on the buckets with pressure energy.
B)
In a reaction turbine, the water glides over the moving vanes with kinetic energy.
C)
In a reaction turbine, the pressure of the flowing water increases after gliding over the vanes.
D)
In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.

Correct Answer :   In an impulse turbine, the pressure of the flowing water remains unchanged and is equal to atmospheric pressure.

38 .
A hydraulic press is a device used
A)
to store pressure energy which may be supplied to a machine later on
B)
to lift larger load by the application of a comparatively much smaller force
C)
to increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure
D)
All of the above

Correct Answer :   to lift larger load by the application of a comparatively much smaller force

39 .
The flow ratio in case of Francis turbine varies from
A)
0.15 to 0.3
B)
0.4 to 0.5
C)
0.6 to 0.9
D)
1 to 1.5

Correct Answer :   0.15 to 0.3

40 .
If V₁ and V₂ are the velocities of water at inlet and outlet of the draft tube respectively, then the efficiency of a draft tube is
A)
V₁ / V₁-V₂
B)
V₁-V₂ / V₁
C)
V₁² / V₁²-V₂²
D)
V₁²-V₂² / V₁²

Correct Answer :   V₁²-V₂² / V₁²

41 .
A Pelton wheel is_______.
A)
inward flow impulse turbine
B)
outward flow impulse turbine
C)
tangential flow impulse turbine
D)
inward flow reaction turbine

Correct Answer :   tangential flow impulse turbine

42 .
The undershot water wheels are those in which
A)
the wheel runs entirely by the weight of water
B)
the wheel runs partly by the weight of water and partly by the impulse of water
C)
the wheel runs entirely by the impulse of water
D)
None of the above

Correct Answer :   the wheel runs entirely by the impulse of water

43 .
The specific speed of a centrifugal pump may be defined as the speed of an imaginary pump, identical with the given pump, which will discharge one litre of water, while it is being raised through a head of one metre.
A)
True
B)
False
C)
Can Not Say
D)
None of the above

Correct Answer :   True

44 .
A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?
A)
Kaplan turbine
B)
Pelton wheel with one nozzle
C)
Francis turbine
D)
Pelton wheel with two or more nozzles

Correct Answer :   Pelton wheel with one nozzle

45 .
Which of the following pump is suitable for small discharge and high heads?
A)
Reciprocating pump
B)
Axial flow pump
C)
Mixed flow pump
D)
Centrifugal pump

Correct Answer :   Reciprocating pump

46 .
The depth of the bucket for a Pelton wheel is generally __________ the diameter of jet.
A)
1.2 times
B)
equal to
C)
1.8 times
D)
double

Correct Answer :   1.2 times

47 .
An impulse turbine is used for
A)
high discharge
B)
low head of water
C)
medium head of water
D)
high head of water

Correct Answer :   high head of water

48 .
Which type of the pump is different from others in the same group?
A)
Gear pump
B)
Screw pump
C)
Plunger pump
D)
Cam and piston pump

Correct Answer :   Plunger pump

49 .
The cavitation in reaction turbines is avoided, to a great extent by
A)
using stainless steel runner of the turbine
B)
providing highly polished blades to the runner
C)
installing the turbine below the tail race level
D)
All of the above

Correct Answer :   All of the above

50 .
A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit power of the wheel is
A)
3.75 kW
B)
1.75 kW
C)
0.75 kW
D)
0.25 kW

Correct Answer :   1.75 kW

51 .
Geometric similarity is said to exist between the model and the prototype, if both of them
A)
have identical velocities
B)
are identical in shape, but differ only in size
C)
have identical forces
D)
are equal in size and shape

Correct Answer :   are identical in shape, but differ only in size

52 .
The ratio of actual work available at the turbine to the energy imparted to the wheel is known as __________ efficiency.
A)
mechanical
B)
overall
C)
hydraulic
D)
None of the above

Correct Answer :   mechanical

53 .
The static head of a centrifugal pump is equal to the __________ of suction head and delivery head.
A)
sum
B)
product
C)
difference
D)
None of the above

Correct Answer :   difference

54 .
In a reaction turbine, the draft tube is used
A)
to run the turbine full
B)
to transport water to downstream
C)
to prevent air to enter the turbine
D)
to increase the head of water by an amount equal to the height of the runner outlet above the tail race

Correct Answer :   to increase the head of water by an amount equal to the height of the runner outlet above the tail race

55 .
The power produced by the reaction turbine is __________ to the head of water.
A)
directly proportional
B)
inversely proportional
C)
Both (A) and (B)
D)
None of the above

Correct Answer :   directly proportional

56 .
Slip of a reciprocating pump is defined as the
A)
sum of actual discharge and the theoretical discharge
B)
difference of theoretical discharge and the actual discharge
C)
ratio of actual discharge to the theoretical discharge
D)
product of theoretical discharge and the actual discharge

Correct Answer :   difference of theoretical discharge and the actual discharge

57 .
The efficiency of a centrifugal pump will be maximum when the blades are bent backward.
A)
Yes
B)
No
C)
Can Not Say
D)
None of the above

Correct Answer :   Yes

58 .
Theoretical power required (in watts) to drive a reciprocating pump is (where w = Specific weight of liquid to be pumped in N/m3, Q = Discharge of the pump in m3/s, Hs = Suction head in metres, and Hd = Delivery head in metres)
A)
wQHs
B)
wQHd
C)
wQ(Hs - Hd)
D)
wQ(Hs + Hd)

Correct Answer :   wQ(Hs + Hd)

59 .
The specific speed of a centrifugal pump, delivering 750 litres of water per second against a head of 15 metres at 725 r.p.m., is
A)
24.8 r.p.m.
B)
48.2 r.p.m
C)
82.4 r.p.m.
D)
248 r.p.m

Correct Answer :   82.4 r.p.m.

60 .
Multi-stage centrifugal pumps are used to
A)
give high discharge
B)
pump viscous fluids
C)
produce high heads
D)
All of the above

Correct Answer :   produce high heads

61 .
The width of the bucket for a Pelton wheel is generally __________ the diameter of jet.
A)
five times
B)
four times
C)
three times
D)
double

Correct Answer :   five times

62 .
For 450 m head of water, __________ shallbeused.
A)
Kaplan turbine
B)
Pelton wheel
C)
Francis turbine
D)
None of the above

Correct Answer :   Pelton wheel

63 .
The speed ratio in case of Francis turbine varies from
A)
1 to 1.5
B)
0.6 to 0.9
C)
0.4 to 0.5
D)
0.15 to 0.3

Correct Answer :   0.6 to 0.9

64 .
Hydraulic Machines fall under the category :
A)
Condensers
B)
Pulverizers
C)
Kinetic machinery
D)
Roto-dynamic machinery

Correct Answer :   Roto-dynamic machinery

Explanation : Hydraulic Machines use the principle of rotation of blades to alter the speed of water. Hence fall under roto dynamic machinery.

65 .
Which type of turbine is a Francis Turbine?
A)
Turgo turbine
B)
Screw Turbine
C)
Reaction turbine
D)
Impulse Turbine

Correct Answer :   Reaction turbine

Explanation : Francis turbine is a reaction turbine as it changes the pressure of water through its process. Hence it cannot be an impulse turbine.

66 .
Which kind of turbines changes the pressure of the water entered through it?
A)
Reaction turbines
B)
Impulse turbines
C)
Kinetic turbines
D)
Reactive turbines

Correct Answer :   Reaction turbines

Explanation : Reaction turbines which act on water try to change the pressure of the water through its motion.

67 .
Which type of turbine is used to change the velocity of the water through its flow?
A)
Impulse turbines
B)
Reaction turbines
C)
Kinetic turbines
D)
Axial flow turbines

Correct Answer :   Impulse turbines

Explanation : In Impulse turbines, potential energy is utilized to convert as kinetic energy thereby changing the velocity of the water through its process.

68 .
Which of the following hydraulic unit is used for transmitting increased or decreased torque to the driven shaft?
A)
Hydraulic ram
B)
Hydraulic accumulator
C)
Hydraulic intensifier
D)
Hydraulic torque converter

Correct Answer :   Hydraulic torque converter

69 .
If the ratio of all the corresponding linear dimensions are equal, then the model and the prototype are said to have
A)
dynamic similarity
B)
geometric similarity
C)
kinematic similarity
D)
None of the above

Correct Answer :   geometric similarity

70 .
In a reaction turbine, the water enters the wheel under pressure and flows over the vanes.
A)
Correct
B)
Incorrect
C)
Can Not Say
D)
None of the above

Correct Answer :   Correct

71 .
The force exerted by a jet of water impinging normally on a plate which due to the impact of jet, moves in the direction of jet with a velocity v is
A)
wa (V-v) / g
B)
wa (V-v) / 2g
C)
wa (V-v)² / g
D)
wa (V-v)² / 2g

Correct Answer :   wa (V-v)² / g

72 .
A reciprocating pump is also called a __________ displacement pump.
A)
positive
B)
negative
C)
Can Not Say
D)
None of the above

Correct Answer :   positive

73 .
In an axial flow reaction turbine, the water flows __________ to the axis of the wheel.
A)
parallel
B)
perpendicular
C)
Can Not Say
D)
None of the above

Correct Answer :   parallel

74 .
A double overhung Pelton wheel has
A)
two jets
B)
two runners
C)
four jets
D)
four runners

Correct Answer :   two runners

75 .
In a centrifugal pump, the water enters the impeller __________ and leaves the vanes axially.
A)
axially
B)
radially
C)
Can Not Say
D)
None of the above

Correct Answer :   radially

76 .
A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit speed of the wheel is
A)
80 r.p.m.
B)
40 r.p.m.
C)
20 r.p.m.
D)
10 r.p.m.

Correct Answer :   20 r.p.m.

77 .
The specific speed of a hydraulic turbine depends upon
A)
speed and head of water
B)
speed and power developed
C)
discharge and power developed
D)
speed, power developed and head of water

Correct Answer :   speed, power developed and head of water

78 .
The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is __________ of the jet velocity,
A)
double
B)
three-fourth
C)
one-half
D)
one-fourth

Correct Answer :   one-half

79 .
By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is
A)
39.2%
B)
48, 8%
C)
84.8%
D)
88.4%

Correct Answer :   84.8%

80 .
The relation between hydraulic efficiency (ηh), mechanical efficiency (ηm) and overall efficiency (ηo) ) is
A)
ηo = ηh x ηm
B)
ηm = ηo x ηh
C)
ηh = ηo x ηm
D)
None of the above

Correct Answer :   ηo = ηh x ηm

81 .
In a Francis turbine runner, the number of blades are generally between
A)
2 to 4
B)
4 to 8
C)
8 to l6
D)
16 to 24

Correct Answer :   16 to 24

82 .
If the Francis turbine is run below 50 percent head for a long period, it will not only lose its efficiency but also the cavitation danger will become more serious.
A)
Agree
B)
Disagree
C)
Can Not Say
D)
None of the above

Correct Answer :   Agree

83 .
Among the following which turbine requires more head?
A)
Tube Turbine
B)
Pelton Turbine
C)
Kaplan Turbine
D)
Francis turbine

Correct Answer :   Pelton Turbine

Explanation : Except Pelton remaining are reaction turbines, in impulse pressure energy is constant and only available energy is kinetic energy which is directly proportional to head.

84 .
Total head of turbines is_______
A)
Pressure head + Static head
B)
Kinetic head + Static head
C)
Static head + Pressure head
D)
Pressure head + Kinetic head + Static head

Correct Answer :   Pressure head + Kinetic head + Static head

Explanation : Generally total is calculated as sum of pressure head, static head and kinetic head.

85 .
Head under which Kaplan turbine is operated______
A)
100-200 meters
B)
70 -100 meters
C)
10-70 meters
D)
Above 200 meters

Correct Answer :   10-70 meters

Explanation : Kaplan turbine is reaction turbine and it operates at low head 10-70 meters and output power is 5-200 MW.

86 .
Under what head is Pelton turbine operated?
A)
20-50 meters
B)
15-2000 meters
C)
60-200 meters
D)
50-500 meters

Correct Answer :   15-2000 meters

Explanation : Pelton turbine is an impulse turbine only energy available is kinetic energy which is proportional to head, hence it requires high head. Theoretically there is no limit to max value of head.

87 .
Head under which Francis turbine is operated?
A)
40-600 meters
B)
70-100 meters
C)
100-200 meters
D)
150-200 meters

Correct Answer :   40-600 meters

Explanation : Francis turbine is also reaction turbine but pressure energy is less when compared with Kaplan turbine. Hence head is between 40 and 600 meters.

88 .
The turbine is preferred for 0 to 25 m head of water?
A)
Kaplan turbine
B)
Tube turbine
C)
Pelton wheel
D)
Francis turbine

Correct Answer :   Kaplan turbine

Explanation : Kaplan is reaction turbine and its range of operation is between 10-70 meters which has output range between 5-200 MW.

89 .
_________ is defined as ratio between power delivered to runner and power supplied at inlet of turbine.
A)
Overall efficiency
B)
Mechanical efficiency
C)
Volumetric efficiency
D)
Hydraulic efficiency

Correct Answer :   Hydraulic efficiency

Explanation : Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine.

90 .
Which among the following which is not an efficiency of turbine?
A)
Mechanical efficiency
B)
Volumetric efficiency
C)
Electrical efficiency
D)
Hydraulic efficiency

Correct Answer :   Electrical efficiency

Explanation : Electrical efficiency is ratio of work output and electrical power input to electrical machine but turbine is a hydraulic machine which consists of only mechanical, volumetric and hydraulic efficiencies.

91 .
The ratio of volume available at shaft of turbine and power supplied at the inlet of the turbine
A)
Hydraulic efficiency
B)
Overall efficiency
C)
Volumetric efficiency
D)
Mechanical efficiency

Correct Answer :   Overall efficiency

Explanation : Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency.

92 .
To obtain maximum hydraulic efficiency of pelton turbine, blade velocity should be ___________ Times the inlet velocity of jet.
A)
Half
B)
Twice
C)
Thrice
D)
One quarter

Correct Answer :   Half

Explanation : Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine. This efficiency will be maximum when differentiating it with “u” and it is obtained as u=v/2.

93 .
Braking jet in an impulse turbine is used
A)
to break the jet of water
B)
to change the direction of runner
C)
to bring the runner to rest in a short time
D)
None of the above

Correct Answer :   to bring the runner to rest in a short time

94 .
The water in a jet propelled boat is drawn through the openings facing the direction of motion of the boat. The efficiency of propulsion is given by
A)
2V / Vr-v
B)
2V / Vr+v
C)
V / Vr-v
D)
V / Vr+v

Correct Answer :   2V / Vr+v

95 .
The ratio of the normal force of jet of water on a plate inclined at an angle of 30° as compared to that when the plate is normal to jet, is
A)
1
B)
1/2
C)
√2
D)
1/√2

Correct Answer :   1/2

96 .
Head developed by a centrifugal pump is
A)
proportional to speed of impeller
B)
proportional to diameter of impeller
C)
proportional to diameter and speed of impeller
D)
None of the above

Correct Answer :   proportional to diameter and speed of impeller

97 .
The expression for maximum hydraulic efficiency of pelton turbine is given by?
A)
(1+cos k)/2 where k is outlet blade angle
B)
(2+cos k)/2 where k is outlet blade angle
C)
(3+cos k)/2 where k is outlet blade angle
D)
(4+cos k)/2 where k is outlet blade angle

Correct Answer :   (1+cos k)/2 where k is outlet blade angle

Explanation : Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine. Its maximum value is obtained by replacing u=v/2 and it is (1+cos k)/2 where k is outlet blade angle

98 .
________ is ratio of volume of water actually striking the runner and volume of water supplied to turbine.
A)
Hydraulic efficiency
B)
Volumetric efficiency
C)
Overall efficiency
D)
Mechanical efficiency

Correct Answer :   Volumetric efficiency

Explanation : Volumetric efficiency is ratio between volume of water actually striking the runner of turbine and volume of water supplied to the turbine.

99 .
Which of the following pump is preferred for flood control and irrigation applications?
A)
Mixed flow pump
B)
Centrifugal pump
C)
Reciprocating pump
D)
Axial flow pump

Correct Answer :   Axial flow pump

100 .
The efficiency of a Pelton wheel working under constant head __________ with the increase in power. remains same increases decreases
A)
increases
B)
decreases
C)
remains same
D)
None of the above

Correct Answer :   increases

101 .
The discharge of a centrifugal pump working under constant head __________ with the speed.
A)
increases
B)
decreases
C)
Can Not Say
D)
None of the above

Correct Answer :   increases

102 .
The discharge of a double acting reciprocating pump is (where L = Length of stroke, A = Cross-sectional area of piston, and N = Speed of crank in r.p.m.)
A)
L.A.N
B)
2 L.A.N
C)
L.A.N / 60
D)
2 L.A.N / 60

Correct Answer :   2 L.A.N / 60

103 .
Work done by a turbine __________ upon the weight of water flowing per second.
A)
depends
B)
does not depend
C)
Can Not Say
D)
None of the above

Correct Answer :   depends

104 .
Which of the following turbine is preferred for 0 to 25 m head of water?
A)
Pelton wheel
B)
Francis turbine
C)
Kaplan turbine
D)
None of the above

Correct Answer :   Kaplan turbine

105 .
The overall efficiency of a reaction turbine is the ratio of
A)
actual work available at the turbine to the energy imparted to the wheel
B)
power produced by the turbine to the energy actually supplied by the turbine
C)
workdone on the wheel to the energy (or head of water) actually supplied to the turbine
D)
None of the above

Correct Answer :   power produced by the turbine to the energy actually supplied by the turbine

106 .
The maximum number of jets, generally, employed in an impulse turbine without jet interference are
A)
two
B)
four
C)
six
D)
eight

Correct Answer :   six

107 .
Discharge (Q) of a centrifugal pump is given by (where D = Diameter of impeller at inlet, b = Width of impeller at inlet, and Vf = Velocity of flow at inlet)
A)
Q = π.b.Vf
B)
Q = π.D.Vf
C)
Q = D.b.Vf
D)
Q = π.D.b.Vf

Correct Answer :   Q = Ï€.D.b.Vf

108 .
A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the
A)
manometric head
B)
static head
C)
kinetic head
D)
velocity head

Correct Answer :   manometric head

109 .
A hydraulic coupling belongs to the category of
A)
energy transfer machines
B)
power absorbing machines
C)
power developing machines
D)
energy generating machines

Correct Answer :   energy transfer machines

110 .
Manometric head, in case of a centrifugal pump, is equal to
A)
Workdone per kN of water - Losses within the impeller
B)
Energy per kN at outlet of impeller - Energy per kN at inlet of impeller
C)
Suction lift + Loss of head in suction pipe due to friction + Delivery lift + Loss of head in delivery pipe due to friction + Velocity head in the delivery pipe
D)
All of the above

Correct Answer :   All of the above

111 .
For centrifugal pump impeller, the maximum value of the vane exit angle is
A)
25° to 30°
B)
20° to 25°
C)
15° to 20°
D)
10° to 15°

Correct Answer :   20° to 25°

112 .
The speed of an imaginary turbine, identical with the given turbine, which will develop a unit power under a unit head, is known as
A)
unit speed
B)
normal speed
C)
specific speed
D)
None of the above

Correct Answer :   specific speed

113 .
The ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as
A)
overall efficiency
B)
volumetric efficiency
C)
manometric efficiency
D)
mechanical efficiency

Correct Answer :   volumetric efficiency

114 .
The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, is
A)
80%
B)
60%
C)
50%
D)
40%

Correct Answer :   50%

115 .
Velocity triangles are used to analyze _________
A)
Measure discharge of flow
B)
Angle of deflection of jet
C)
Flow of water along blades of turbine
D)
Flow of water, measure of discharge, angle of deflection

Correct Answer :   Flow of water, measure of discharge, angle of deflection

Explanation : By using velocity triangles we can determine discharge of flow, angle of deflection of jet and to measure relative velocity of jet with respect to speed of wheel.

116 .
In which of following turbine inlet and outlet blade velocities of vanes are equal?
A)
Pelton turbine
B)
Kaplan turbine
C)
Francis turbine
D)
Propeller turbine

Correct Answer :   Pelton turbine

Explanation : In Pelton turbine each blade has same angular velocity and same linear speed unlike Francis and Kaplan turbines.

117 .
Manometric head is the actual head of water against which a centrifugal pump has to work.
A)
Correct
B)
Incorrect
C)
Can Not Say
D)
None of the above

Correct Answer :   Correct

118 .
The overall efficiency for a Pelton wheel lies between
A)
0.50 to 0.65
B)
0.65 to 0.75
C)
0.75 to 0.85
D)
0.85 to 0.90

Correct Answer :   0.85 to 0.90

119 .
The hydraulic efficiency of an impulse turbine is the
A)
ratio of the actual work available at the turbine to the energy imparted to the wheel
B)
ratio of the work done on the wheel to the energy of the jet
C)
ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
D)
None of the above

Correct Answer :   ratio of the work done on the wheel to the energy of the jet

120 .
By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power.The saving in case of a double acting reciprocating pump is
A)
39.2%
B)
48.8%
C)
84.8%
D)
88.4%

Correct Answer :   39.2%

121 .
A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is
A)
0.26
B)
0.36
C)
0, 46
D)
0.56

Correct Answer :   0, 46

122 .
In a reciprocating pump, air vessels are used to
A)
smoothen the flow
B)
reduce suction head
C)
increase delivery head
D)
reduce acceleration head

Correct Answer :   reduce acceleration head

123 .
If the ratio's of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have.
A)
geometric similarity
B)
dynamic similarity
C)
kinematic similarity
D)
None of the above

Correct Answer :   dynamic similarity

124 .
The discharge through a reaction turbine __________ with the increase in unit speed.
A)
increases
B)
decreases
C)
remains same
D)
None of the above

Correct Answer :   decreases

125 .
Which of the following pump is generally used to pump highly viscous fluid?
A)
Screw pump
B)
Air lift pump
C)
Centrifugal pump
D)
Reciprocating pump

Correct Answer :   Screw pump

126 .
A hydraulic intensifier is a device used to increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure.
A)
Correct
B)
Incorrect
C)
Can Not Say
D)
None of the above

Correct Answer :   Correct

127 .
In order to avoid cavitation in centrifugal pumps
A)
the suction pressure should be low
B)
the delivery pressure should be low
C)
the suction pressure should be high
D)
the delivery pressure should be high

Correct Answer :   the suction pressure should be high

128 .
The hydraulic efficiency of a reaction turbine, is the ratio of
A)
actual work available at the turbine to energy imparted to the wheel
B)
power produced by the turbine to the energy actually supplied by the turbine
C)
Both (A) and (B)
D)
workdone on the wheel to the energy (or head of water) actually supplied to the turbine

Correct Answer :   workdone on the wheel to the energy (or head of water) actually supplied to the turbine

129 .
The Thomson's turbine is __________ reaction turbine.
A)
a mixed flow
B)
an inward flow
C)
an axial flow
D)
an outward flow

Correct Answer :   an inward flow

130 .
Which of the following pump is sucessfully used for lifting water to the boilers?
A)
Jet pump
B)
Air-lift pump
C)
Centrifugal pump
D)
Reciprocating pump

Correct Answer :   Jet pump

131 .
Which of the following pump is successfully used for lifting water from deep wells?
A)
Jet pump
B)
Centrifugal pump
C)
Reciprocating pump
D)
Air lift pump

Correct Answer :   Air lift pump

132 .
Slip of a reciprocating pump is negative, when
A)
delivery pipe is long and pump is running at high speeds
B)
suction pipe is short and pump is running at low speeds
C)
suction pipe is long and delivery pipe is short and the pump is running at high speeds
D)
suction pipe is short and delivery pipe is long and the pump is running at low speeds

Correct Answer :   suction pipe is long and delivery pipe is short and the pump is running at high speeds

133 .
The Furneyron turbine is __________ reaction turbine.
A)
a mixed flow
B)
an axial flow
C)
an outward flow
D)
an inward flow

Correct Answer :   an outward flow

134 .
The discharge through a turbine is
A)
directly proportional to H1/2
B)
inversely proportional to H1/2
C)
directly proportional to H3/2
D)
inversely proportional to H3/2

Correct Answer :   directly proportional to H1/2

135 .
Which of the following is not an impulse turbine?
A)
Pelton wheel
B)
Kaplan turbine
C)
Turgo turbine
D)
Girad turbine

Correct Answer :   Kaplan turbine

136 .
A hydraulic accumulator is a device used to store __________ energy which may be supplied to a machine later on.
A)
pressure
B)
strain
C)
kinetic
D)
None of the above

Correct Answer :   pressure

137 .
Overall efficiency of a centrifugal pump is the ratio of
A)
energy supplied to the pump to the energy available at the impeller
B)
manometric head to the energy supplied by the impeller per kN of water
C)
energy available at the impeller to the energy supplied to the pump by the prime mover
D)
actual workdone by the pump to the energy supplied to the pump by the prime mover

Correct Answer :   actual workdone by the pump to the energy supplied to the pump by the prime mover

138 .
The impeller of a centrifugal pump may have
A)
volute casing
B)
vortex casing
C)
volute casing with guide blades
D)
any one of these

Correct Answer :   any one of these

139 .
Kinematic similarity is said to exist between the model and the prototype, if both of them
A)
have identical forces
B)
are equal in size and shape
C)
have identical velocities
D)
are identical in shape, but differ only in size

Correct Answer :   have identical velocities

140 .
In Pelton wheel, if outlet velocity angle of jet is "acute angled" then outlet whirl velocity of jet is _______
A)
Zero
B)
x- component of V(r2) – blade velocity
C)
x- component of V (r2) + blade velocity
D)
Blade velocity – x- component of V (r2)

Correct Answer :   x- component of V(r2) – blade velocity

Explanation : By constructing velocity triangle we come to know that whirl velocity of jet is equal in magnitude to that of x- component of V r2 – blade velocity.

141 .
In Pelton wheel if angle of deflection is not mentioned then we assume it as__________
A)
165 degrees
B)
185 degrees
C)
200 degrees
D)
225 degrees

Correct Answer :   165 degrees

142 .
In Pelton turbine ___________ is defined as ratio between power delivered to runner and power supplied at inlet of turbine.
A)
Volumetric efficiency
B)
Hydraulic efficiency
C)
Overall efficiency
D)
Mechanical efficiency

Correct Answer :   Hydraulic efficiency

Explanation : Hydraulic efficiency is defined as ratio between power given by water to runner of turbine and to the power supplied by water at inlet of the turbine.

143 .
In Pelton turbine product of mechanical efficiency and hydraulic efficiency is known as ______
A)
Hydraulic efficiency
B)
Volumetric efficiency
C)
Overall efficiency
D)
Mechanical efficiency

Correct Answer :   Overall efficiency

Explanation : Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency.

144 .
In the expression for overall efficiency of turbine, which is p/ (k*g*q*h), where "k" is known as _______
A)
Density of liquid
B)
Volume of liquid
C)
Specific density of liquid
D)
Specific gravity of liquid

Correct Answer :   Density of liquid

Explanation : Overall efficiency is defined as ratio of power available at shaft of turbine to power supplied at the inlet of turbine which is also product of mechanical and hydraulic efficiency. Its expression is given by p/ (k*g*q*h) where k is density of liquid.

145 .
The expression for hydraulic efficiency is given by
A)
2(V1-u)[1+cos k]u/V1*V1
B)
2(V1+u)[1+cos k]u/V1*V1
C)
2(V1-u)[1-cos k]u/V1*V1
D)
2(V1+u)[1+cos k]u/V1*V1

Correct Answer :   2(V1-u)[1+cos k]u/V1*V1

Explanation : Hydraulic efficiency is ratio of power delivered to runner to power supplied at inlet of turbine upon substituting the mathematical terms we get expression as follows.

Where, V1=inlet jet velocity, u=blade velocity, k=outlet blade angle

146 .
Radial flow reaction turbines are those turbines in which water flows ________
A)
Axial direction
B)
Tangential direction
C)
Both (A) and (B)
D)
Radial direction

Correct Answer :   Radial direction

Explanation : The name itself indicates the type of flow that is radial direction but the thing that is unknown is whether it is radially inward or outwards.

147 .
Discharge through radial flow reaction turbine is _______
A)
P1*b1*Vf1
B)
P2*b2*Vf2
C)
P1*b2*Vf2
D)
Both P1*b1*Vf1 & P2*b2*Vf2

Correct Answer :   Both P1*b1*Vf1 & P2*b2*Vf2

Explanation : Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes.

Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=thickness and Vf=flow velocity.

148 .
_________ consists of stationary circular wheel all around the runner of turbine
A)
Runner
B)
Guide mechanism
C)
Casing
D)
Drafting

Correct Answer :   Guide mechanism

Explanation : Guide vanes are placed around the runner to regulate the flow and to provide shock less entry at inlet to runner.

149 .
The casing of radial flow reaction turbine is made of spiral shape, so that water may enter the runner_____
A)
Variable velocity
B)
Variable acceleration
C)
Constant velocity
D)
Constant acceleration

Correct Answer :   Constant velocity

Explanation : Area of spiral structure gradually decreases because as discharge decreases correspondingly area also decreases. So, runner will rotate with constant velocity.

150 .
The pressure at the exit of runner of reaction turbine is generally____________than atmospheric pressure
A)
Lesser
B)
Equal
C)
Greater
D)
Constant

Correct Answer :   Lesser

Explanation : In general, the exit of runner has a low pressure compared to the atmospheric pressure.

151 .
_________is a pipe of gradually increasing area used for discharging water from exit of the turbine to the tail race.
A)
Runner
B)
Casing
C)
Draft tube
D)
Guide mechanism

Correct Answer :   Draft tube

Explanation : Draft is a pipe of gradually increasing area, as water leaving runner has less pressure, draft tube will increase pressure energy of water by decreasing its velocity.

152 .
___________and __________of radial flow reaction turbine are always full of water.
A)
Casing and penstocks
B)
Runner and penstocks
C)
Runner and draft tube
D)
Casing and runner

Correct Answer :   Casing and runner

Explanation : Casing and runner are completely covered by water as it is a reaction turbine in which pressure energy is predominant.

153 .
The water from penstocks enters the _____ which is spiral in shape which the area of cross section of casing goes on decreasing gradually
A)
runner
B)
casing
C)
draft tube
D)
guide wheel

Correct Answer :   casing

Explanation : The water from penstocks enters the casing which is spiral in shape in which the area of cross section of casing decreases gradually.

154 .
If the water flows from inwards to outwards, the turbine is known as _____
A)
Inward flow turbine
B)
Tangential flow turbine
C)
Turbulent low inward flow
D)
Outward flow turbine

Correct Answer :   Outward flow turbine

Explanation : If the water in the runner flows from inwards to outwards, then such type of turbine is said to be outward radial flow turbine.

155 .
In general, reaction turbines consist of which types of energies?
A)
kinetic energy and pressure energy
B)
kinetic energy and potential energy
C)
potential energy and pressure energy
D)
gravitational energy and potential energy

Correct Answer :   kinetic energy and pressure energy

Explanation : Reaction turbine is a kind of turbine in which the water at inlet of the turbine possesses both kinetic energy and pressure energy.

156 .
In an outward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as ________
A)
Discharge
B)
Flow ratio
C)
Speed ratio
D)
Radial discharge

Correct Answer :   Flow ratio

Explanation : Flow ratio is known as ratio of tangential wheel at inlet to given velocity of jet and it is scalar quantity.

157 .
__________is ratio of pressure energy change inside runner to total energy change inside runner
A)
Flow ratio
B)
Speed ratio
C)
Degree of reaction
D)
Hydraulic efficiency

Correct Answer :   Degree of reaction

Explanation : This is just a formula and it is scalar quantity because it is ratio of two changes of energies.

158 .
Degree of reaction for reaction turbine is _____
A)
1- cot x /2(cot x –cot y)
B)
1+ cot x /2(cot x –cot y)
C)
1- cot x /2(cot x +cot y)
D)
1+ cot x /2(cot x +cot y)

Correct Answer :   1- cot x /2(cot x –cot y)

Explanation : Because for reaction turbine Vw2=0 and V2=Vf2, there is also no much change in velocity of flow implies that Vf1=Vf2 by substituting these values, we get it.

159 .
The Pelton wheel extracts energy from_______
A)
Vane angle
B)
Heat rejection
C)
Moving fluid
D)
Increase in temperature

Correct Answer :   Moving fluid

Explanation : The Pelton wheel extracts energy from moving of fluid. When the fluid flows through the Pelton wheel, a kinetic energy is developed. This kinetic energy is extracted from the moving fluid.

160 .
In impulse turbines with stationary blades, there is_________ in blades of the turbine.
A)
Same pressure
B)
Volumetric change
C)
Pressure independent
D)
Pressure change

Correct Answer :   Pressure change

Explanation : In impulse turbines, there is pressure change in blades of the turbine. There is pressure change that is developed in fluid or gas in the turbine blades. The turbine blades are in stationary condition.

161 .
In an inward flow reaction turbine the discharge ______
A)
Increases
B)
Decreases
C)
Independent
D)
None of the above

Correct Answer :   Decreases

Explanation : In an inward flow reaction turbine the discharge of fluid decreases. Thus, making it different from an outward flow reaction turbine.

162 .
Inward radial flow reaction turbine is a turbine in which water flows across the blades of runner________
A)
Radially inward
B)
Axial direction
C)
Radial direction
D)
Radially outward

Correct Answer :   Radially inward

Explanation : The name itself indicates that flow is in radial direction and flowing from outer periphery towards center.

163 .
Which of following is inward radial flow reaction turbine?
A)
Axial turbine
B)
Francis turbine
C)
Pelton wheel
D)
Kaplan turbine

Correct Answer :   Francis turbine

Explanation : Pelton is impulse a turbine, Kaplan is axial flow turbine and Francis is an inward flow reaction turbine.

164 .
The main difference between reaction turbine and inward radial flow reaction turbine is water flows______
A)
Axial direction
B)
Radially outward
C)
Radially inward
D)
Radial direction

Correct Answer :   Radially inward

Explanation : The name itself indicates the type of flow that is radial direction but the thing that is unknown is whether it is radially inward or outwards.

165 .
In Inward radial flow reaction turbine if thickness is considered then discharge is _______
A)
(P1-n*t)*b1*Vf1
B)
(P2-n*t)*b2*Vf2
C)
(P1-n*t)*b2*Vf2
D)
Both (P1-n*t)*b1*Vf1 & (P2-n*t)*b2*Vf2

Correct Answer :   Both (P1-n*t)*b1*Vf1 & (P2-n*t)*b2*Vf2

Explanation : Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes. If n blades of thickness t is considered then discharge is (P1-n*t)*b1*Vf1.

Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=width, Vf=flow velocity, n=number of blades and t=thickness of blades

166 .
In Inward radial flow reaction turbine if angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at outlet is _________
A)
Flow ratio
B)
Speed ratio
C)
Radial inlet discharge
D)
Radial outlet discharge

Correct Answer :   Radial outlet discharge

Explanation : If angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at outlet in radial flow reaction then total velocity will be flow velocity.

167 .
Tendency of wheel to race is almost nil in ___________turbine.
A)
Inward flow reaction turbine
B)
Impulse turbine
C)
Axial flow turbine
D)
Outward flow reaction turbine

Correct Answer :   Inward flow reaction turbine

Explanation : In an inward reaction flow turbine, wheel moves with the constant speed.

168 .
What is the water flow direction in the runner in a Francis turbine?
A)
Axial and then radial
B)
Radial and then axial
C)
Axial and then tangential
D)
Tangential and then axial

Correct Answer :   Radial and then axial

Explanation : Francis turbine is radial flow reaction turbine. Though the water enters the turbine tangentially, it enters the runner radially inward and flows outward along the axis of the runner.

169 .
Why does the cross sectional area of the Spiral casing gradually decrease along the circumference of the Francis turbine from the entrance to the tip?
A)
To prevent leakage from the turbine
B)
To reduce material costs in order to make the turbine more economical
C)
To ensure constant velocity of water during runner entry
D)
To prevent loss of efficiency of the turbine due to impulsive forces caused by extra area

Correct Answer :   To ensure constant velocity of water during runner entry

Explanation : The primary purpose of the gradual decrease in area is so that the runner sees constant velocity of water at each point of entry. Absence of this may lead to inefficiency. The spiral casing is used to prevent leakage from the turbine but the gradual decrease in area is not for that reason.

170 .
Which of the following runner types will have the highest vane angle at inlet (β1 value)?
A)
Slow Runner
B)
Fast Runner
C)
Medium Runner
D)
None of the above

Correct Answer :   Fast Runner

Explanation : Considering the velocity diagram of Francis turbine at the inlet for a fast runner, vane angle is an obtuse angle. Whereas, it is right angle for medium runner and an acute angle for a slow runner.

171 .
In case of a Medium runner, tan (α1) CANNOT be given by (α1 = Guide vane angle at inlet)?
A)
Vw1 / u1
B)
Vr1 / u1
C)
Vr1 / Vw1
D)
Vf1 / Vw1

Correct Answer :   Vw1 / u1

Explanation : In medium runner, Vf1 = Vr1 & Vw1 = u1. Vw1 and u1 are along the same direction, hence that cannot be written as tan (α1).

172 .
Which of the following efficiencies for Francis Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet?
A)
Overall efficiency
B)
Mechanical efficiency
C)
Volumetric efficiency
D)
Hydraulic efficiency

Correct Answer :   Hydraulic efficiency

Explanation : The definition of Hydraulic efficiency in a Francis turbine states that it is the ratio between the Runner power to the shaft power. Hence, the correct option is Hydraulic efficiency.

173 .
Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet?
A)
Overall efficiency
B)
Volumetric efficiency
C)
Hydraulic efficiency
D)
Mechanical efficiency

Correct Answer :   Overall efficiency

Explanation : The definition of Overall efficiency in a Francis turbine states that it is the ratio between the Shaft power to the Water power. Hence, the correct option is Overall efficiency.

174 .
The input water power of the Francis turbine is 1.25 times the runner power. What would be the hydraulic efficiency of the turbine (in %)?
A)
60
B)
70
C)
80
D)
90

Correct Answer :   80

Explanation : The definition of Hydraulic efficiency in a Francis turbine states that it is the ratio between the Runner power to the shaft power. If input water power is 1.25 times the runner power, the runner power is 1/1.25 = 0.8 Times the water power. Hence, hydraulic efficiency = 80%.

175 .
The volume flow rate of water in 10 m³/s at an available head of 60 m (g = 10 m/s³). Find the shaft power (in MW) if the overall efficiency of the turbine is 90%.
A)
0.54
B)
5.4
C)
54
D)
540

Correct Answer :   5.4

Explaination : The overall efficiency of a Francis turbine is given by ηo = shaft power/ ρQgH. Substituting the given values in this equation, we get shaft power = 5.4 MW.

176 .
In a Kaplan turbine, what is the direction of water flow?
A)
Radial and then axial
B)
Axial and then axial
C)
Tangential and then axial
D)
Tangential and then radial

Correct Answer :   Axial and then axial

Explanation : The Kaplan turbine is an axial flow reaction turbine. The water inlet is axial and the water outlet is axial too.

177 .
In this type of low head turbine, the guide vanes are fixed to the hub of the turbine and are not adjustable. What is this type of turbine called?
A)
Kaplan Turbine
B)
Francis turbine
C)
Pelton turbine
D)
Propeller Turbine

Correct Answer :   Francis turbine

Explanation : In a Kaplan turbine, the guide vanes are adjustable and not fixed to the hub of the turbine. Francis and Pelton turbines are not low head turbines. In a propeller turbine, the guide vanes are fixed to the hub of the turbine.

178 .
Which of the following turbines will have the lowest number of blades in it?
A)
Kaplan turbine
B)
Steam turbine
C)
Pelton turbine
D)
Francis turbine

Correct Answer :   Kaplan turbine

Explanation : As the head for Kaplan turbine is low, the discharge of water through the turbine is high and hence, blade resistance should be low. That’s why Kaplan turbine will have the lowest number of blades.

179 .
Which of the following efficiencies for Kaplan Turbine is described as the ratio between the power produced by runner to the power supplied by water at the inlet?
A)
Overall efficiency
B)
Volumetric efficiency
C)
Mechanical efficiency
D)
Hydraulic efficiency

Correct Answer :   Hydraulic efficiency

Explanation : The definition of Hydraulic efficiency in a Kaplan turbine states that it is the ratio between the Runner power to the shaft power. Hence, the correct option is Hydraulic efficiency.

180 .
It is given that the input water power of the Kaplan turbine is 1.10 times the runner power. What would be the hydraulic efficiency of the turbine (in %)?
A)
70.71
B)
80.81
C)
90.91
D)
100.00

Correct Answer :   90.91

Explanation : The definition of Hydraulic efficiency in a Kaplan turbine states that it is the ratio between the Runner power to the shaft power. If input water power is 1.10 times the runner power, the runner power is 1/1.10 = 0.90909 Times the water power. Hence, hydraulic efficiency = 90.91%.