Hydroelectric Power Plant Multiple Choice Questions and Answers
Hydroelectric Power Plant Multiple Choice Questions and Answers
Introduction of Hydroelectric Power Plant Objective Questions and Answers
1. Hydroelectric power plant is __________
a) Non-renewable source of energy
b) Conventional source of energy
c) Non-conventional source of energy
d) Continuous source of energy
Answer: Conventional source of energy
2. Which statement about hydroelectric power plant is wrong?
a) Efficiency of hydroelectric power plant does not reduce with age
b) Its construction coast is very high and takes a long time for erection.
c) It is very neat and clean plant because no smoke or ash is produced.
d) Meeting rapidly changing load demands is not possible in hydroelectric power plant.
Answer: Meeting rapidly changing load demands is not possible in hydroelectric power plant.
3. Which of the following is not a requirement for site selection of hydroelectric power plant?
a) Availability of water
b) Large catchment area
c) Rocky land
d) Sedimentation
Answer: Sedimentation
4. Which of the following is the correct equation for the electrical power generated by the hydroelectric power plant?
a) 75×0.736 wQHη Watt
b) (7.5/0.736) × wQHη Watt
c) 0.845 ×wQHη Watt
d) 9.81 ×wQHη
Answer: 0.845 ×wQHη Watt
5. The amount of electrical energy that can be generated by a hydroelectric power plant depends upon ___________
a) Head of water
b) Quantity of water
c) Specific weight of water
d) Efficiency of Alternator
Answer: Quantity of water
6. Which of the following is not an advantage of hydroelectric power plant?
a) no fuel requirement
b) low running cost
c) continuous power source
d) no standby losses
Answer: continuous power source
7. Hydroelectric power plant is mainly located in ____________
a) Flat areas
b) Deserts
c) Hilly areas
d) Deltas
Answer: Hilly areas
8. Which of the following statement is true about hydroelectric power plant?
a) Hydroelectric power plants are multipurpose.
b) Due to non-uniform flow of water frequency control in such plants is very difficult.
c) Hydroelectric power plant has high running cost
d) Water is used as fuel in hydroelectric power plant
Answer: Hydroelectric power plants are multipurpose.
9. In a hydro-electric plant,spillways are used _________
a) To discharge all surplus water
b) To discharge surplus water on the downstream side of dam
c) Water is not not available in sufficient quantity
d) None of the above
Answer: To discharge surplus water on the downstream side of dam
10. For high head hydro-electric plants,the turbine used is _________
a) Pelton wheel
b) Francis
c) Kaplan
d) All of the above
Answer: Pelton wheel
11. The cost of fuel transportation is minimum _________
a) Thermal power plant
b) Hydro-electric power plant
c) Nuclear power plant
d) None of the above
Answer: Hydro-electric power plant
12. The power output from a hydro-electric power plant depends on three parameters _________
a) Head,type and dam of discharge
b) discharge and efficiency of the system
c) Efficiency of the system,type of draft tube and type of turbine used
d) Type of dam,discharge and type of catchment area
Answer: Head,discharge and efficiency of the system
13. Operating charges are minimum in the case of _________ for same power output
a) Gas turbine plant
b) Hydel plant
c) Thermal plant
d) Nuclear plant
Answer: Hydel plant
14. The cheapest plant in operation and maintenance is _________
a) Staem power plant
b) Nuclear power palnt
c) Hydro-electric power plant
d) None of the above
Answer: Hydro-electric power plant
14. Gross head of a hydro power station is _________
a) The difference of water level between the level in the storage and tail race
b) The height of the water level in the river where the storage is provided
c) The height of the water level in the river where the tail race is provided
d) None of the above
Answer: The difference of water level between the level in the storage and tail race
15. The cheapest plant in operation and maintenance is _________
a) Staem power plant
b) Nuclear power palnt
c) Hydro-electric power plant
d) None of the above
Answer: Hydro-electric power plant
16. The annual depriciation of a hydro power plant is about _________
a) 0.5% to 1.5%
b) 10% to 15%
c) 15% to 20%
d) 20% to 25%
Answer: 0.5% to 1.5%
17. The running cost of hydro-electric power plant is _________ paise per unit
a) 10
b) 8
c) 5
d) 15
Answer: 5
18. In high head hydro power plant the velocity of water in penstock is about _________
a) 1 m/s
b) 4 m/s
c) 7 m/s
d) 12 m/s
Answer: 7 m/s
19. Hydroelectric power plant is generally located near load centre.
a) True
b) False
Answer: False
20. Potential energy of water is used to drive the turbine.
a) True
b) False
Answer: False
Elements of Hydroelectric Power Plant Objective Questions and Answers
1. The pressure at the inlet or exit of the draft tube should not be _________
a) less than one third of atmospheric pressure
b) greater than one third of atmospheric pressure
c) less than one atmospheric pressure
d) greater than one atmospheric pressure
Answer: less than one third of atmospheric pressure
2. Trash racks are built for ___________
a) discharging the water freely from the turbine exit to tailrace
b) preventing the turbine from ingress of floating and other materials
c) creating artificial head to store sufficient potential energy of water
d) controlling the opening of valves
Answer: preventing the turbine from ingress of floating and other materials
3. Dam having very wide base as compared to its height is called _________
a) buttress dam
b) arch dam
c) earth dam
d) solid gravity dam
Answer: earth dam
4. Which statement about surge tank is wrong?
a) Ideal location of surge tank is at the turbine inlet
b) A decrease in load demands cause a rise in water level in surge tank
c) Surge tanks are totally closed to avoid entry of unwanted objects to penstock
d) Surge tanks are installed to reduce harm effects of water hammer phenomenon
Answer: Surge tanks are totally closed to avoid entry of unwanted objects to penstock
5. Location of the surge tank in a hydro-electric station is near to the ________
a) Tailrace
b) Turbine
c) Reservoir
d) None of the above
Answer: Reservoir
6. The function of a surge tank is _______
a) To supply water at constant pressure
b) To produce surges in the pipe line
c) To relieve water hammer pressures in the penstock pipe
Answer: To relieve water hammer pressures in the penstock pipe
7. Which element of hydroelectric power plant prevents the penstock from water hammer phenomenon?
a) Valves and Gates
b) Draft tubes
c) Spillway
d) Surge Tank
Answer: Surge Tank
8. Penstock in a hydroelectric power plant is _____________
a) a pipe connected to runner outlet
b) nozzle that release high pressure water on turbine blades
c) a conduit connecting forebay to scroll case of turbine
d) a pipe connecting surge tank to dam
Answer: a conduit connecting forebay to scroll case of turbine
9. What is the function of booms?
a) It supports the dam
b) It supports the penstock
c) It divert the Icebergs from flowing into the penstock
d) To hold the turbine structure
Answer: It supports the dam
8. Trash racks are located _____________
a) near tailrace
b) at the entrance of turbine
c) inside penstock
d) intake
Answer: intake
9. Draft tube increases the operating head on the turbine.
a) True
b) False
Answer: True
10. Spillway discharges the overflow water to the downstream side when the reservoir is full.
a) True
b) False
Answer: True
Water Turbine of Hydroelectric Power Plant Objective Questions and Answers
1. Which of the following is not a reaction turbine?
a) Francis turbine
b) Kaplan turbine
c) Pelton wheel turbine
d) Propeller turbine
Answer: Pelton wheel turbine
2. Which turbine has highest speed?
a) Pelton wheel turbine
b) Francis turbine
c) Impulse turbine
d) Kaplan turbine
Answer: Kaplan turbine
3. Inside pressure of which of the following turbine is equal to atmospheric pressure?
a) Fixed vane propeller turbine
b) Movable vane propeller turbine
c) Francis turbine
d) Pelton wheel turbine
Answer: Pelton wheel turbine
4. Pelton turbines are used for _______________
a) medium head applications
b) low head applications
c) in steam power plants
d) for high head applications
Answer: for high head applications
5. Operating head of Francis turbine is __________
a) less than 30
b) less than 70 m
c) 30 to 200 m
d) more than 200 m
Answer: 30 to 200 m
6. Francis turbines are the type of _____________
a) reaction turbines
b) radial flow turbine
c) impulse turbine
d) axial flow turbine
Answer: reaction turbines
7. Governing mechanism used in case of Pelton wheel turbine is ________
a) guide vane
b) nozzle needle
c) control valve
d) dam gates
Answer: nozzle needle
8. Kaplan turbine is _____________
a) axial flow turbine
b) inward flow turbine
c) tangential flow turbine
d) mixed flow turbine
Answer: axial flow turbine
9. Guide vanes are used as governor in Kaplan turbine.
a) True
b) False
Answer: True
10. Francis turbine is suitable for medium head hydroelectric power plant.
a) True
b) False
Answer: True
Pelton Wheel Turbine of Hydroelectric Power Plant Objective Questions and Answers
1. Pelton wheel turbine is used for minimumof the following heads __________
a) 40 m
b) 120 m
c) 150 m
d) 180 m or above
Answer: 180 m or above
2. For centrifugal pump impeller, what is the maximum value of the vane exit angle?
a) 100 to 150
b) 150 to 200
c) 200 to 250
d) 250 to 300
Answer: 200 to 250
3. What is the formula for the velocity of water jet at the inlet of turbine?
Where,
H = Net head acting on Pelton wheel
Cv = coefficient of velocity of jet
a) V = Cv((gH)(1/2))
b) V = 2Cv((gH)(1/2))
c) V = Cv((2gH)(1/2))
d) V = 2Cv((gH)(1/2))
Answer: V = Cv((2gH)(1/2))
4. Which of the following is an example of impulse turbine?
a) Propeller turbine
b) Francis turbine
c) Kaplan turbine
d) Pelton wheel
Answer: Pelton wheel
5. What is the head of water available at turbine inlet in hydro-electric power plant called?
a) head race
b) tail race
c) gross head
d) net head
Answer: net head
6. Which of the following pump is preferred for flood control and irrigation applications?
a) Reciprocating pump
b) Axial flow pump
c) Mixed flow pump
d) Centrifugal pump
Answer: Axial flow pump
7. In which turbine the pressure energy of water is first converted into kinetic energy by means of nozzle kept close to the runner?
a) Impulse turbine
b) Reaction turbine
c) Both Impulse and Reaction turbine
d) None of the mentioned
Answer: Impulse turbine
7. What is runaway speed of the runner of Pelton wheel?
a) maximum unsafe speed of the runner due to sudden increase in load on turbine
b) minimum safe speed of the runner due to sudden increase in load on turbine
c) maximum unsafe speed of the runner due to sudden decrease in load on turbine
d) minimum safe speed of the runner due to sudden decrease in load on turbine
Answer: maximum unsafe speed of the runner due to sudden decrease in load on turbine
8. The runner of __________ turbine always be under pressure of above atmospheric pressure.
a) Turgo
b) Girand
c) Kaplan
d) None of the mentioned
Answer: Kaplan
9. Power required to drive a centrifugal pump is directly proportional to __________ of its impeller.
a) cube of diameter
b) fourth power of diameter
c) diameter
d) square of diameter
Answer: fourth power of diameter
10. Gross head is the difference between __________
a) head race and tail race
b) head race and net head
c) head race and friction losses
d) net head and friction losses
Answer: head race and tail race
11. The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is __________
a) high speed with radial flow at outlet
b) slow speed with radial flow at outlet
c) medium speed with radial flow at outlet
d) high speed with axial flow at outlet
Answer: high speed with axial flow at outlet
12. The pressure of water is atmospheric and remains constant while passing over the runner in __________
a) Impulse turbine
b) Reaction turbine
c) Both Impulse and Reaction turbine
d) None of the mentioned
Answer: Impulse turbine
13. The energy of water entering the reaction turbine is _______
a) fully the kinetic energy
b) fully the pressure energy
c) partly the pressure energy and partly the kinetic energy
d) unpredictable
Answer: partly the pressure energy and partly the kinetic energy
14. In a reaction turbine, the draft tube is used __________
a) to increase the head of water by an amount equal to the height of the runner outlet above the tail race
b) to transport water to downstream
c) to run the turbine full
d) to prevent air to enter the turbine
Answer: to increase the head of water by an amount equal to the height of the runner outlet above the tail race
15. Pelton turbines are mostly ________
a) Horizontal
b) Vertical
c) Inclined
d) None of the above
Answer: Horizontal
Kaplan, Francis and Deriaz Turbines of Hydroelectric Power Plant Objective Questions and Answers
1. The working of which of the following hydraulic units is based on Pascal’s law?
a) Hydraulic coupling
b) Air lift pump
c) Jet pump
d) Hydraulic press
Answer: Hydraulic press
2. Which of the following turbine is preferred for 0 to 25 m head of water?
a) Kaplan Turbine
b) Pelton Turbine
c) Francis Turbine
d) None of the mentioned
Answer: Kaplan Turbine
3. 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
Answer: volumetric efficiency
4. What is the mechanical efficiency of an impulse turbine?
a) ratio of the actual power produced by the turbine to the energy actually supplied by the turbine
b) ratio of the actual work available at the turbine to the energy imparted to the wheel
c) ratio of the Work done on the wheel to the energy of the jet
d) none of the mentioned
Answer: ratio of the actual work available at the turbine to the energy imparted to the wheel
5. Which of the following pump is generally used to pump highly viscous fluid?
a) Air lift pump
b) Centrifugal pump
c) Screw pump
d) Reciprocating pump
Answer: Air lift pump
6. 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) terrific speed
c) specific velocity
d) specific speed
Answer: specific speed
7. 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) 84.8%
b) 74.8%
c) 64.8%
d) 54.8%
Answer: 84.8%
8. A Francis turbine is used when the available head of water is?
a) 0 to 25 m
b) 25 to 250 m
c) > 250 m
d) none of the mentioned
Answer: 25 to 250 m
9. The maximum efficiency of jet propulsion of a ship with inlet orifices at right angles to the direction of motion of ship, will be?
a) 40%
b) 50%
c) 60%
d) 80%
Answer: 50%
10. 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
Answer: 0.56
11. The maximum number of jets, generally, employed in an impulse turbine without jet interference are __________
a) 2
b) 6
c) 7
d) 5
Answer: 2
12. In a Francis turbine runner, the number of blades are generally between __________
a) 2 to 4
b) 8 to 16
c) 4 to 8
d) 16 to 24
Answer: 16 to 24
13. In a reciprocating pump, air vessels are used to __________
a) increase delivery head
b) reduce suction head
c) smoothen the flow
d) reduce acceleration head
Answer: reduce acceleration head
14. 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) work done on the wheel to the energy actually supplied to the turbine
d) none of the mentioned
Answer: work done on the wheel to the energy actually supplied to the turbine
15. The impeller of a centrifugal pump may have __________
a) vortex casing
b) volute casing
c) volute casing with guide blades
d) any of the mentioned
Answer: any of the mentioned
16. Kinematic similarity is said to exist between the model and the prototype, if both of them __________
a) are equal in size and shape
b) have identical velocities
c) are identical in shape, but differ only in size
d) have identical forces
Answer: have identical velocities
17. If the ratios of the corresponding forces acting at corresponding points are equal, then the model and the prototype are said to have __________
a) kinematic similarity
b) geometric similarity
c) dynamic similarity
d) none of the mentioned
Answer: dynamic similarity
18. The cups at the periphery of the Pelton wheel are __________
a) equiangular
b) equidistant
c) equimolar
d) none of the mentioned
Answer: equidistant
19. 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 mentioned
Answer: power produced by the turbine to the energy actually supplied by the turbine
20. Manometric head, in case of a centrifugal pump, is equal to __________
a) 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
b) Energy per kN at outlet of impeller – Energy per kN at inlet of impeller
c) Workdone per kN of water – Losses within the impeller
d) All of the mentioned
Answer: All of the mentioned
21. A hydraulic coupling belongs to the category of __________
a) power absorbing machines
b) energy transfer machines
c) power developing machines
d) energy generating machines
Answer: energy transfer machines
22. A centrifugal pump will start delivering liquid only when the pressure rise in the impeller is equal to the __________
a) manometric head
b) velocity head
c) kinetic head
d) static head
Answer: manometric head
23. Multi-stage centrifugal pumps are used to __________
a) produce high heads
b) give high discharge
c) pump viscous fluids
d) all of the mentioned
Answer: produce high heads
24. Geometric similarity is said to exist between the model and the prototype if both of them __________
a) are equal in size and shape
b) have identical velocities
c) have identical forces
d) are identical in shape, but differ only in size
Answer: are identical in shape, but differ only in size
25. Discharge of a centrifugal pump is __________
a) inversely proportional to (diameter)2 of its impeller
b) inversely proportional to diameter of its impeller
c) directly proportional to (diameter)2 of its impeller
d) directly proportional to diameter of its impeller
Answer: inversely proportional to (diameter)2 of its impeller
26. Slip of a reciprocating pump is defined as the __________
a) sum of actual discharge and the theoretical discharge
b) ratio of actual discharge to the theoretical discharge
c) difference of theoretical discharge and the actual discharge
d) product of theoretical discharge and the actual discharge
Answer: difference of theoretical discharge and the actual discharge
27. Francis and kaplan turbine is used for _________ heads hydro-electric plant.
a)Medium and low head
b) High head
c) Low head
d) Low and high head
Answer: Medium and low head
28. Francis,kaplan and propeller turbines fall under the category of ________
a) Impulse turbine
b) Reaction turbine
c) Impulse reaction combined
d) Axial flow
Answer: Reaction turbine
29. Francis turbine is usually used for _______
a) Low head installation upto 30 m
b) Medium head installation from 30 m to 180 m
c) High head installation above 180 m
d) For all heads
Answer: Medium head installation from 30 m to 180 m
30. The runner of Kaplan turbine always be under pressure of above atmospheric pressure
a) True
b) False
Answer: True
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