1. Which of the following provides energy for winds to blow naturally?
a) Sun
b) Water
c) Man
d) Food
Answer: a
2. Wind flows from _______ pressure area to ________ pressure area.
a) high, high
b) high, low
c) low, high
d) low, low
Answer: b
3. What is a gust?
a) No change in wind speed
b) A brief decrease in wind speed for a very long period of time
c) A brief increase in wind speed for a very short period of time
d) A brief increase in wind speed for a very long period of time
Answer: c
4. What is a squall?
a) A sudden, sharp increase in wind speed lasting for a few hours
b) A sudden, sharp decrease in wind speed lasting for a few minutes
c) A sudden, sharp decrease in wind speed lasting for a few hours
d) A sudden, sharp increase in wind speed lasting for a few minutes
Answer: d
5. A windstorm _______
a) is strong enough to cause property damage
b) is not stronger than gust
c) does not exist
d) is not strong enough to cause property damage
Answer: a
6. What are planetary or prevailing winds?
a) Winds not blowing from one latitude to another
b) Winds blowing from one latitude to another
c) Gusts
d) Winds that do not cover large areas of earth
Answer: b
7. Which of the following are the two most important planetary winds?
a) Hosting
b) Trades and economics
c) Trade winds and westerly winds
d) Deployment
Answer: c
8. What are trade winds?
a) Winds blowing from equatorial low pressure areas to sub-tropical high pressure areas
b) Winds that trade with each other
c) Winds blowing from equatorial high pressure areas to sub-tropical low pressure areas
d) Winds blowing from sub-tropical high pressure areas to equatorial low pressure areas
Answer: d
9. How does Coriolis effect trade winds in Northern Hemisphere?
a) Coriolis effect deflects trade winds to the right
b) Coriolis effect deflects trade winds to the left
c) Coriolis effect does not affect the trade winds in Northern Hemisphere
d) Coriolis effect only affects the trade winds in Southern Hemisphere
Answer: a
10. How does Coriolis effect trade winds in Southern Hemisphere?
a) Coriolis effect deflects trade winds to the right
b) Coriolis effect deflects trade winds to the left
c) Coriolis effect does not affect the trade winds in Southern Hemisphere
d) Coriolis effect only affects the trade winds in Northern Hemisphere
Answer: b
11. Trade winds ______
a) do not maintain a constant direction but blow steadily
b) maintain a constant direction but do not blow steadily
c) maintain a constant direction and blow steadily
d) shrinking technique
Answer: c
12. What are westerly winds?
a) Winds blowing from sub-tropical high pressure areas to sub-polar low pressure areas
b) Winds that trade with each other
c) Winds blowing from equatorial high pressure areas to sub-tropical low pressure areas
d) Winds blowing from equatorial low pressure areas to sub-tropical high pressure areas
Answer: a
13. Westerly winds of Southern Hemisphere ______
a) weaker and maintain a constant direction than its counterpart in Northern Hemisphere
b) are stronger and maintain a constant direction than its counterpart in Northern Hemisphere are
c) are stronger but do not maintain a constant direction than its counterpart in Northern Hemisphere
d) blow from equatorial low pressure areas to sub-tropical high pressure areas
Answer: b
14. What are periodic winds?
a) Westerly winds
b) Winds that do not change their direction periodically with the change in season
c) Winds that change their direction periodically with the change in season
d) Trade winds
Answer: c
15. Which of the following are examples of periodic winds?
a) Gusts
b) Windstorm
c) Westerly winds
d) Monsoons, land and sea breeze, mountain and valley breeze
Answer: d
16. A downburst is created by an area of rain-cooled air that _____
a) after hitting the ground generates strong winds which spread in all directions
b) don’t hit the ground
c) after hitting the ground generates extremely weak winds which spreads in all directions
d) are short gusts
Answer: a
17. What is sea breeze?
a) Winds that don’t strike the ground level
b) Winds from sea that flow during day towards the land and replace the lighter and rising hot air
c) Winds that hit the land to generate extremely weak winds which spreads in all directions
d) Short gusts originating from sea
Answer: b
18. What is land breeze?
a) Winds that hit the sea to generate extremely weak winds which spreads in all directions
b) Winds from land that flow during night towards the sea and replace the lighter and rising hot air
c) Winds from sea that flow towards the land and replace the lighter and rising hot air
d) Short gusts originating from land
Answer: c
19. Which of the following equations best explains the phenomenon of winds flowing from high pressure to low pressure?
a) Pressure = Force/Area
b) Roult’s law
c) Force = mass*acceleration
d) Ideal gas equation
Answer: d
20. How do thunderstorms form?
a) Thunderstorms originate from a pleasant breeze
b) Thunderstorms are produced by mid-level clouds
c) Thunderstorms are produced by cumulonimbus cloud which generated gusty winds and heavy rains
d) Thunderstorms originate from low-level clouds and do not carry rain with them
Answer: c
21. Which of the following are types of winds?
a) Planetary winds, periodic winds, local winds
b) Trade winds, westerly winds, plate tectonics
c) Apples, monsoon
d) Clouds, rains, storms
Answer: a
22. What is considered as a strong breeze on a Beaufort Wind Scale?
a) 0
b) 6
c) 1
d) 4
Answer: b
23. Which of the following is not an application of wind energy?
a) Electricity
b) Steam engine
c) Agriculture
d) Energy storage for emergencies
Answer: b
24. Which of the following sports use wind energy?
a) Wind surfing
b) Chess
c) Carroms
d) Kho-Kho
Answer: a
25. Does the team sport cricket, use wind?
a) True
b) False
Answer: a
26. How is wind energy used in flourmills?
a) To beat corn grains into paste
b) To beat wheat grains into paste
c) To grind wheat and corn grains into flour
d) Wind energy is not used in flourmills
Answer: c
27. Which of the following wind turbine is mostly used to extract wind energy?
a) DC generator
b) Vertical-axis wind turbines
c) Sailing boat
d) Horizontal-axis wind turbines
Answer: d
28. Wind energy is not used to pump water to a higher level.
a) True
b) False
Answer: b
29. _______ light is used to denote dangers of birds, bats or/and airplanes.
a) Red
b) Blue
c) Yellow
d) Green
Answer: a
30. Which of the following is a mechanical application of wind energy?
a) Lighting
b) Electricity
c) Pumping water
d) Wind surfing
Answer: c
31. Which of the following is a potential application of wind energy?
a) Converting heat to wind energy
b) Converting electrical energy to wind energy
c) Transportation of electrical energy
d) Converting the wind flow due to speeding cars into electricity on highways
Answer: d
32. Does flying a kite use wind energy?
a) True
b) False
Answer: a
33. How is drag force experienced by the blade reduced in various modern blade designs?
a) Bending and tapering the blade
b) Using heavy metals
c) Twirling the blade
d) Increasing the length of the blade
Answer: a
34. What is angle of attack?
a) Angle between downwind side and upwind side
b) Angle between the blade and the rotor
c) Angle between the direction of wind and pitch of the blade
d) Angle between the blade and the wind tower
Answer: c
35. When plotting lift vs angle of attack, which of following best describes the shape of the curve?
a) Exponential
b) Cubic
c) Linear
d) Parabolic
Answer: d
36. There is no ideal angle of attack for best rotation.
a) True
b) False
Answer: b
37. The speed at the tip of the blade is faster than its center.
a) True
b) False
Answer: a
38. What is the angle by which the rotor blades are twisted?
a) 5-10 degrees
b) 15-45 degrees
c) 100-120 degrees
d) 10-20 degrees
Answer: d
39. Which of the following blade designs further increases the efficiency of airfoil blades?
a) Twisting and tapering the blades
b) Reducing wind tower height
c) Increasing wind tower height
d) Increasing rotor speed
Answer: a
40. Why is a blade twisted along its length rather than its width?
a) Drag reduction
b) Weight reduction
c) Drag reduction and improvement in angle of attack
d) Aesthetic reasons
Answer: c
41. Which of the following blade designs further increases the efficiency of airfoil blades?
a) Reducing wind tower height
b) Twisting and tapering the blades
c) Increasing wind tower height
d) Increasing rotor speed
Answer: b
42. Why does wind speed increase with height above ground?
a) More slip boundary conditions
b) Less obstructions and no slip boundary conditions
c) More obstructions and slip boundary conditions
d) Gas molecules have less mass
Answer: b
43. Increased wind tower height and longer blades do not result in an increase in power.
a) True
b) False
Answer: b
44. Why should longer turbine blades be made of stronger materials?
a) Longer turbine blades experience greater forces
b) Longer turbine blades experience lesser forces
c) Stronger materials are cheaper
d) Stronger materials are available in abundance
Answer: a
45. Which of the following is best reason for not using longer blades even though they produce greater output power?
a) Longer turbine blades experience greater forces
b) Longer turbine blades experience lesser forces
c) Safety concerns due to greater momentum of longer blades
d) Stronger materials are available in abundance
Answer: c
46. Which theory is used to model the wind turbine?
a) Blade element momentum theory
b) Kinetic gas theory
c) Archimedes principle
d) Einstein’s theory of photoelectric effect
Answer: a
47. What is blade element momentum theory?
a) It is same as blade element theory
b) It is same as momentum theory
c) It talks about the motion of a body in a given frame of reference
d) It is used to calculate the local forces on the propeller or blade
Answer: d
48. What is the main disadvantage of a horizontal axis wind turbine?
a) Easy operation at near ground winds
b) Does not self-start
c) Difficult operation at near ground winds
d) High starting torque
Answer: c
49. Which of the following materials are used to make a rotor blade of a wind turbine?
a) Glass fibre reinforced polyester
b) Salt
c) Sugar
d) Plastic
Answer: a
50. Which of the following materials can be used to make a rotor blade of a wind turbine apart from glass fibre reinforced polyester (GRP)?
a) Silicon, germanium
b) Epoxy, carbon fibre
c) Plastic
d) Salt
Answer: b
51. Fatigue testing of rotor blades subject the blades to an oscillation in _______ direction.
a) horizontal
b) vertical
c) flapwise
d) diagonal
Answer: c
52. Which of the following are the major parts of a wind turbine system?
a) Tower, rotor, water storage tank, air compressor
b) Tower, rotor and blades, air compressor, vacuum pump, electricity generator
c) Electricity generator, nacelle, rotor and blades, power converter, building
d) Tower, nacelle, rotor and blades, power converter, electricity generator
Answer: d
53. What is the main function of tower in a wind turbine system?
a) Acts a support to all other components used in wind turbine system
b) Acts as an antenna for wireless radio communications
c) Acts as an electric pole for power transportation
d) Destabilizes the wind turbine system
Answer: a
54. Which of the following towers is used for small wind turbines?
a) Hybrid tower
b) Guyed pole tower
c) Electric pole
d) Wooden pole
Answer: b
55. What is a hybrid type tower?
a) Guyed tower
b) Guyed tower and wooden tower
c) Thin and tall lattice type guyed tower
d) Guyed tower and electric pole
Answer: c
56. Nacelle is a kiosk that houses ______
a) a MOSFET
b) a diode
c) a wifi router
d) a yaw drive
Answer: d
57. What is the main function of gearbox in a wind turbine system?
a) Multiples rotation speed to generate electricity
b) Divides rotation speed to generate electricity
c) Multiples rotation speed to consume wind energy
d) Divides rotation speed to consume wind energy
Answer: a
58. What is a pitch drive motor?
a) A motor that senses wind direction
b) A motor to control the angle of blades
c) A motor to ensure nacelle faces in the direction of the wind
d) A motor to rotate the blades
Answer: b
59. What is a yaw drive?
a) A device used to support and stabilize other components
b) A device used to house various energy conversion components
c) A motor to ensure that nacelle faces the wind
d) A device used to track wind direction
Answer: c
60. What is the cost of a wind turbine per megawatt?
a) $10000
b) $1000
c) $100
d) $1 million
Answer: d
61. Wind turbines require regular maintenance.
a) False
b) True
Answer: b
62. Offshore wind turbines are not erected in water bodies.
a) False
b) True
Answer: a
63. What happens to wind speed when many turbines operate collectively?
a) Wind speed reduces
b) Wind speed increases
c) Wind speed does not change
d) Wind speed increases exponentially and then decreases linearly
Answer: a
64. Which of the following is true?
a) More than 50% of the land area on earth can generate 1W per square meter
b) Less than 5% of the land area on earth can generate 1W per square meter
c) 60 – 80% of the land area on earth can generate 1W per square meter
d) More than 80% of the land area on earth can generate 1W per square meter
Answer: b
65. Lower wind speeds result in ________
a) higher wind energy obtained
b) no wind energy obtained
c) lower wind energy obtained
d) 100% energy conversion for half the operation time and less than 10% energy conversion for the remaining half of the operation time
Answer: c
66. What happens to the output power when the wind turbine blades rotate faster for the entire operation time?
a) The output power first increases then decreases
b) The output power first decreases then monotonically increases
c) The output power decreases
d) The output power increases
Answer: d
67. Higher wind speeds _________ the speed of rotation of the wind blades.
a) increase
b) decrease
c) monotonically decrease
d) first increase and then decrease
Answer: a
68. What is cut-in wind speed?
a) Wind turbine stops generating output power
b) Wind turbine starts generating output power
c) Wind turbine stops functioning
d) Wind turbine starts functioning
Answer: b
69. What is rated speed?
a) Wind turbines generate least output power
b) Wind turbines do not generate any output power
c) Wind turbines generate maximum output power
d) Wind turbines have no rated speed as the output power always increases
Answer: c
70. Which of the following are the limits of the range of wind speeds for which the turbines are designed?
a) Elasticity
b) Threshold voltage
c) Networking
d) Cut-in speed and cut-out speed
Answer: d
71. How does the output power vary between cut-in speed and the rated speed?
a) cubically
b) linearly
c) square
d) exponential
Answer: a
72. What is the cut-out speed?
a) Wind turbine starts generating output power
b) Wind turbine must be shut down
c) Wind turbine stops functioning
d) Wind turbine starts functioning but does not generate output power
Answer: b
73. Power output is not related to the local air density.
a) False
b) True
Answer: a
74. Which of the following does the local air density depend upon?
a) Soil
b) Lightning
c) Altitude and pressure
d) Nitrogen and oxygen
Answer: c
75. Higher air density leads to higher power output.
a) True
b) False
Answer: a
76. What is feather of wind turbine blades?
a) Adding feathers to the blades
b) Reducing the weight of wind turbine blades
c) Reducing the angle of pitch
d) Increasing the angle of pitch
Answer: d
77. Why is feathering of wind turbine blades required?
a) To increase drag
b) To reduce drag
c) To prevent the blades from being destroyed by strong winds
d) To extract power from strong winds originating from storms
Answer: c
78. What is depth of discharge?
a) Percentage of the battery that is discharged during a cycle
b) Percentage of the battery that is discharged
c) Amount of charge discharged from a battery during a cycle
d) Amount of charge discharged from a battery
Answer: a
79. What is charge-to-discharge ratio?
a) Time taken to charge the device
b) Ratio of time taken to charge the device relative to the time taken to discharge the device
c) Ratio of the amount of charge during charging cycle to the amount of charge during discharge cycle
d) Time taken to discharge the device
Answer: b
80. What is memory effect?
a) Electro-hydrogen generation
b) Pumped storage
c) Remembering a charging level
d) Electric grid
Answer: c
81. Which of the following have large power (>50MW) and storage capacities (>100MWh)?
a) Memory effect
b) Battery energy storage (BES) and flow battery energy storage
c) Super capacitor energy storage and flywheel energy storage
d) Pumped hydro-electric storage and underground pumped hydro-electric storage
Answer: d
82. Efficiency of pumped hydro-electric storage is in the range of _________
a) 50% — 80%
b) 80% — 120%
c) 10% — 20%
d) 45% — 50%
Answer: a
83. How does pumped hydro-electric storage work?
a) Pumps water from higher level to a lower level
b) Pumps water from lower level to higher level
c) Uses electrical energy present in the water
d) Uses nuclear energy present in the water molecules
Answer: b
84. Which of the following is an application of pumped hydro-electric storage?
a) Energy source
b) Frequency regulation only in pumping mode
c) Frequency regulation in both pumping and generation modes
d) Absorbs power to increase the net expenses
Answer: c
85. What is a major disadvantage with pumped hydro-electric system?
a) No dependence on geographical locations
b) Small scale construction for effective functioning
c) Low initial costs of construction
d) Depends on specific geographical locations for the construction of the two reservoirs
Answer: d
86. Which of the following best indicates the flow diagram of storage mode in compressed air energy storage?
a) Power from grid → motor → compressor → storage
b) Power from grid → motor → storage → compressor
c) Power from grid → compressor → motor → storage
d) Motor → power from grid → compressor → storage
Answer: a
87. Which of the following best indicates the flow diagram of power generation mode in compressed air energy storage?
a) Storage → LPT → HPT → generator
b) Storage → HPT → LPT → generator
c) Storage → LPT → generator → HPT
d) HPT → Storage →LPT → generator
Answer: b
88. Which of the following are used for large scale battery energy storage?
a) Li-ion batteries
b) Capacitors
c) Lead acid
d) Reservoirs
Answer: c
89. How does a flow battery energy storage work?
a) Electrolyte tanks → pumps → electrodes → current
b) Electrolyte tanks → pumps → current → electrodes
c) Electrolyte tanks → current → electrodes → pumps
d) Electrolyte tanks → electrodes → current → pumps
Answer: a
90. The central shaft in a flywheel energy storage device rotates on two magnetic bearings.
a) False
b) True
Answer: b
91. Flywheels are used in uninterrupted power supply (UPS).
a) True
b) False
Answer: a
92. Capacitors do not suffer from ________
a) dielectric breakdown
b) material dependence
c) excess electric potential
d) memory effect
Answer: d
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