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WorksheetsPower System-1
Total questions: 80
Worksheet time: 1hrs 20mins
Name
Class
Date
1.
Out of the following which one is not a unconventional source of energy ?
a)
Tidal power
b)
Geothermal energy
c)
Nuclear energy
d)
Wind power.
2.
In India largest thermal power station is located at
a)
Kota
b)
Sarni
c)
Chandrapur
d)
Neyveli
3.
The percentage 02 by volume in atmosphere air is
a)
0.21
b)
0.23
c)
0.77
d)
0.79
4.
Solar thermal power generation can be achieved by
a)
using focusing collector or heliostates
b)
using flat plate collectors
c)
using a solar pond
d)
any of the above system
5.
The overall efficiency of thermal power plant is equal to
a)
Rankine cycle efficiency
b)
Carnot cycle efficiency
c)
Regenerative cycle efficiency
d)
Boiler efficiency x turbine efficiency x generator efficiency
6.
Economiser is used to heat
a)
air
b)
feed water
c)
flue gases
d)
all above
7.
The modern steam turbines are
a)
impulse turbines
b)
reaction turbines
c)
impulse-reaction turbines
d)
none of the above
8.
The draught which a chimney produces is called
a)
induced draught
b)
natural draught
c)
forced draught
d)
balanced draught
9.
Artificial draught is produced by
a)
induced fan
b)
forced fan
c)
induced and forced fan
10.
The amount of energy available in the wind at any instant is proportional to ___ of the wind speed.
a)
Square root power of two
b)
Square root power of three
c)
Square power
d)
Cube power
11.
Wind energy is harnessed as ______ energy with the help of windmill or turbine.
a)
Mechanical
b)
Solar
c)
Electrical
d)
Heat
12.
Winds having following speed are suitable to operate wind turbines.
a)
5 – 25m/s
b)
10 – 35m/s
c)
20 – 45m/s
d)
30 – 55m/s
13.
What does Heating and cooling of the atmosphere generates?
a)
Thermo line circulation
b)
Radiation currents
c)
Convection currents
d)
Conduction currents
14.
How much is the energy available in the winds over the earth surface is estimated to be?
a)
2.9 X 120 MW
b)
1.6 X 107 MW
c)
1 MW
d)
5MW
15.
How much wind power does India hold?
a)
20,000 MW
b)
12,000 MW
c)
140,000 MW
d)
5000 MW
16.
What is the main source for the formation of wind?
a)
Uneven land
b)
Sun
c)
Vegetation
d)
Seasons
17.
Which country created wind mills?
a)
Egypt
b)
Mongolia
c)
Iran
d)
Japan
18.
“During the day, the air above the land heats up more quickly than the air over water”.
a)
true
b)
false
19.
What type of energy is wind energy?
a)
Renewable energy
b)
Non-renewable energy
c)
Conventional energy
d)
Commercial energy
20.
At what range of speed is the electricity from the wind turbine is generated?
a)
100 – 125 mph
b)
450 – 650 mph
c)
250 – 450 mph
d)
30-35 mph
21.
When did the development of wind power in India began?
a)
1965
b)
1954
c)
1990
d)
1985
22.
The term photo voltaic comes from ________
a)
Spanish
b)
Greek
c)
German
d)
English
23.
The volt is the units of emf that was named after its inventor _________
a)
Alessandro volta
b)
Alxender volta
c)
Alexa volta
d)
Alexandro volta
24.
When the source of light is not sun light then the photo voltaic cell is used as ____________
a)
Photo diode
b)
Photo voltaic cell
c)
Photo detector
d)
Photo transmitter
25.
The region where the electrons and holes diffused across the junction is called ________
a)
Depletion Junction
b)
Depletion region
c)
Depletion space
d)
Depletion boundary
26.
The current produce by the solar cell can be given by _________
a)
IL – ID + ISh
b)
IL + ID – ISh
c)
IL + ID + ISh
d)
IL – ID – ISh
27.
The amount of photo generated current increases slightly with increase in _________
a)
Temperature
b)
Photons
c)
Diode current
d)
Shunt current
28.
Solar cells are made from bulk materials that are cut into wafer of _________ thickness.
a)
120-180μm
b)
120-220μm
c)
180-220μm
d)
180-240μm
29.
__________ is one of the most important materials is also known as solar grade silicon.
a)
Crushed silicon
b)
Crystalline silicon
c)
Powdered silicon
d)
Silicon
30.
__________ photo voltaic devices in the form of thin films.
a)
Cadmium Telluroide
b)
Cadmium oxide
c)
Cadmium sulphide
d)
Cadmium sulphate
31.
Organic polymer solar cells are made from Polyphenylene.
a)
true
b)
false
32.
The generating voltage and frequency in India is about?
a)
11 kV and 60 Hz
b)
11 kV and 50 Hz
c)
220 kV and 60 Hz
d)
220 kV and 50 Hz
33.
Which type of system is generally adopted for the generation and transmission of electrical power?
a)
3 phase 4 wire
b)
2 phase 3 wire
c)
3 phase 3 wire
d)
None of these
34.
The rated voltage of a 3 phase power system is given by
a)
rms peak voltage
b)
Peak phase voltage.
c)
rms line to line voltage
d)
Peak line to line voltage.
35.
Which of these systems uses the 3 phase 4 wire system?
a)
Primary distribution
b)
Secondary distribution
c)
Primary transmission.
d)
Secondary transmission.
36.
With the same maximum voltage to earth, which among the following ac systems with 0.8 pf will need more copper compared to 2 wire system?
a)
Single phase, 2 wire
b)
Single phase, 3 wire
c)
Three phase, 3 wire
d)
Three phase, 4 wire
37.
A transmission and distribution engineer needed to design the sub transmission substation. The tapping component needed will be _______________
a)
feeder
b)
distributor
c)
transmitter
d)
tap-changing transformer
38.
While designing the distribution to locality of one lac population with medium dense load requirement, we can employ ___________
a)
radial system
b)
parallel system
c)
ring main system
d)
any of the mentioned
39.
A _________ distribution system is more reliable than the ______ distribution system.
a)
parallel, radial
b)
parallel, ring
c)
radial, parallel
d)
ring, parallel
40.
A DC 2-wire system with mid-point earthed having cross-sectional area of each conductor be ‘a’ and resistance ‘R1’. If the DC tow wire replaces the system, then the ratio of volume of each conductor V1/V2 will be ___________
a)
¼
b)
½
c)
4
d)
2
41.
While designing the distribution sub stations by the designer, it is required to use the _______ for the discrete power tapping.
a)
distributor
b)
power transformer
c)
distribution transformer
d)
feeder
42.
A DC 2-wire system with mid-point earthed having cross-sectional area of each conductor be ‘a’ and resistance ‘R1’. If this is replaced by monopolar system, then saving of copper will be ______
a)
½
b)
¼
c)
2
d)
4
43.
For the single phase 2-wire system, the maximum voltage between the outer wires and earth is ______________
a)
V/√2
b)
√2V
c)
V
d)
2V
44.
For the given distribution system the maximum voltage at the midpoint will be ________
a)
155.6 V
b)
311.12 V
c)
622 V
d)
220 V
45.
Which of the following is not the transmission voltage in india
a)
66
b)
132
c)
400
d)
264
46.
Which of the following is usually not the generating voltage (in KV)?
a)
6.6
b)
9.9
c)
11
d)
13.2
47.
Boosters are basically
a)
inductors
b)
capacitors
c)
transformers
d)
synchronous motors.
48.
Which of the following is not the distribution system normally used
a)
3 phase-4 wire
b)
3 phase-3 wire
c)
Single phase - 3 wire
d)
Single phase -4 wire.
49.
Conductors for high voltage transmission lines are suspended from towers
a)
to reduce clearance from ground
b)
to increase clearance from ground
c)
to reduce wind and snow loads
d)
to take care of extension in length during summer.
50.
Transmission efficiency increases as
a)
voltage and power factor both increase
b)
voltage and power factor both decrease
c)
voltage increases but power factor decreases
d)
voltage decreases but power factor increases.
51.
With same maximum voltage to earth, which ac system (with p.f. 0.8) will require more copper as compared to dc 2 wire system
a)
single phase. 2 wire (mid point earthed)
b)
single phase. 3 wire (neutral=1/2 outer)
c)
three phase three wire
d)
three phase-four wire (neutral = outer).
52.
When alternating current passes through a conductor
a)
it remains uniformly distributed throughout the section of conductor
b)
portion of conductor near the surface carries more current as compared to the core
c)
portion of conductor near the surface carries less current as compared to the core
d)
entire current passes through the core of the conductor.
53.
The fact that a conductor carries more current on the surface as compared to core, is known as
a)
skin effect
b)
corona
c)
permeability
d)
unsymmetrical fault.
54.
The effective resistance of a conductor will be the same as ohmic resistance when
a)
current is in true sine wave form
b)
voltage is low
c)
power factor is unity
d)
Current is uniformly distributed in the conductor cross-section.
55.
Skin effect results in
a)
reduced effective resistance but increased effective internal reactance of the conductor
b)
increased effective resistance but reduced effective internal reactance of. the conductor
c)
reduced effective resistance as well as effective internal reactance
d)
increased effective resistance as well as effective internal reactance.
56.
Skin effect depends on
a)
size of the conductor
b)
frequency of the current
c)
resistivity of the conductor material
d)
all of the above.
57.
The skin effect of a conductor will reduce as the
a)
diameter increases
b)
frequency increases
c)
permeability of conductor material increases
d)
resistivity of conductor material increases.
58.
Skin effect is proportional to
a)
diameter of conductor
b)
(diameter of conductor)1/2
c)
(diameter of conductor )2
d)
none
59.
In overhead transmission lines the effect of capacitance can be neglected when the length of line is less than
a)
200 km
b)
160 km
c)
100 km
d)
80 km.
60.
A synchronous motor takes the leading current when it is
a)
Overexcited
b)
Under excited
c)
Not excited
d)
Either over or under excited
61.
To reduce the power consumption, the capacitors should be located
a)
As close as possible to the load
b)
As far as possible to the load
c)
Not too close not too far from the load
d)
None of these
62.
If an alternator is supplying load of 350 kW at 0.6 pf lagging and its power factor is raised to unity then to supply the alternator for the same kVA loading, the extra required kilowatts will be
a)
205 kW
b)
212 kW
c)
233 kW
d)
246 kW
63.
In order to improve the power factor of equipment operating at lagging power factor, a capacitor is connected
a)
In series with the equipment
b)
In parallel with the equipment
c)
In series-parallel with the equipment
d)
None of these
64.
Phase advancers are used to improve the power factor of
a)
Induction motors
b)
Induction generators
c)
Synchronous motors
d)
Synchronous generators
65.
Power factor of a load can be improved by using
a)
Static capacitors
b)
Synchronous condenser
c)
Phase advancer
d)
All of the above
66.
If power factor is less than unity then it will result in
a)
Large kVA rating of equipment
b)
Greater conductor size
c)
Large copper losses
d)
All of the above
67.
If the load current decreases then the power factor
a)
Will also decrease
b)
Will increase
c)
Will remains unchanged
d)
None of these
68.
The wattles component is
a)
I
b)
I cos∅
c)
I sin∅
d)
None of these
69.
Which one of the following loads has the poorest power factor?
a)
Electric fan Induction motor
b)
Transformer
c)
Induction motor
d)
Induction furnace
70.
Which one is NOT the cause of the decrease in power factor?
a)
Decrease in system voltage.
b)
Increase in air gap in induction motor.
c)
Operating equipment at part load
d)
Operating synchronous motor with over excitation
71.
Which one of the following statements is NOT true?
a)
When the equipment is designed at low power factor it is to be designed for more kVA
b)
When power factor is decreased, loss in the cable supplying load is decreased.
c)
Due to reduced power factor voltage regulation of line becomes poor
d)
Reduced power factor reduces the efficiency of the plant
72.
Earthing is necessary to give protection against
a)
Danger of electric shock
b)
Voltage fluctuation
c)
Overloading
d)
High temperature of the conductors
73.
Solid grounding is addopted for voltages below
a)
100 V
b)
200 V
c)
400 V
d)
660 V
74.
The advantage of neutral earthing is
a)
Freedom from persistent arcing grounds
b)
Over voltages due to lightning can be discharged to earth
c)
Simplified design earth fault protection
d)
All of the above
75.
In a star connected system without neutral grounding, zero sequence currents are
a)
Zero
b)
Phaser sum of phase currents
c)
Same as r.m.s. value of phase currents
d)
Same as peak value of phase currents
76.
The advantage of neutral earthing
a)
Safety of personnel
b)
Reduction of earth fault current
c)
Elemination of arcing ground
d)
None of the above
77.
What is the amount of charcoal and salt needed for GI Pipe earthing?
a)
Charcoal 5 kg, salt 8 kg
b)
Charcoal 10 kg, salt 8 kg
c)
Charcoal 10 kg, salt 10 kg
d)
Charcoal 5 kg, salt 5 kg
78.
What should be the value of earthing resistance for large power stations?
a)
1 Ω
b)
0.5 Ω
c)
2 Ω
d)
5 Ω
79.
What type of earthing is used by transmission lines?
a)
Plate earthing
b)
Rod earthing
c)
Strip earthing
d)
All of these
80.
Which type of earthing is also called as ‘fire earthing’?
a)
Plate earthing
b)
Rod earthing
c)
Strip earthing
d)
All of these
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