Resistance switching is normally resorted in case of
A
Air blast CB
B
Bulk oil CB
C
Minimum oil CB
D
All types of CB
Question 2Single Answer
By transmitting power at high voltage
A
it will give poor voltage regulation
B
it will give better voltage regulation
C
it will not effect voltage regulation
D
None of these
Question 3Single Answer
Which statement about the daily load curve is valid ?
A
The area under the curve gives the average demand
B
The ratio of the area under the curves to the total area of rectangle in which it is contained gives the load factor for the day
C
The peak of the curve gives the installed capacity of the plant
D
The area of the curves divided by the number of hours gives load factor
Question 4Single Answer
High voltage Schring bridge is used to measure
A
large capacitance without additional element
B
small capacitance without additional element
C
medium value capacitance
D
None of these
Question 5Single Answer
Draw - in - system of laying underground cables has the drawback (s) of
A
higher cost
B
reduced current carrying capacity of the cables
C
requirements of much deeper and wider trenches
D
repairs, alterations or additions difficult
E
all of the above except
Question 6Single Answer
Surge impedance of a transmission line is
A
independent of its length
B
dependent on its length
C
independent on its temperature
D
none of the above
Question 7Single Answer
If two synchronous generators connected in parallel loose synchronism, it will lead to
A
stalling of generators
B
wild fluctuations in current
C
wild fluctuations in current and voltage
D
None of these
Question 8Single Answer
A differential relay responds to
A
algebraic difference of two or more similar electrical quantities
B
vector difference of two or more similar electrical quantities
C
algebraic difference between two currents
D
algebraic difference between two voltages
Question 9Single Answer
The conductor carries more current on the surface in comparison to its core. This phenomenon is called the
A
Skin effect
B
Corona
C
Ferranti effect
D
Lenz's effect
Question 10Single Answer
A booster is connected in
A
series with the feeder
B
parallel with the feeder
C
both (a) and (b) are correct
D
none of these
Question 11Single Answer
Fuses have got advantages of
A
cheapest type of protection
B
inverse time - current characteristic
C
no maintenance
D
current limiting effect under short - circuit conditions
E
all of the above
Question 12Single Answer
The power transmitted will be maximum when
A
line reactance is high
B
corona losses are minimum
C
sending end voltage is more
D
receiving end voltage is more
Question 13Single Answer
The connected load of a consumer is 2 kW and his maximum demand is 1.5 kW. The load factor of the consumer is
A
0.75
B
0.375
C
1.33
D
None of these
Question 14Single Answer
In a transformer, the exciting current will be in phase quadrature with the impressed voltage provided
A
only the leakage impedance drop is ignored
B
only the core loss is ignored
C
both the leakage impedance drop and the core loss are ignored
D
only the no - load copper loss is ignored
Question 15Single Answer
Which of the following techniques is used for the measurements of a.c. high frequency voltages ?
A
Peak voltmeter
B
Series resistance mircro - ammeter
C
Resistance potential divider
D
All of these
Question 16Single Answer
Use of additional shunt capacitor can be made for increasing the capability of line as it
A
reduces surge impedance Z0
B
increases phase shift β
C
increase in α
D
all of the above
Question 17Single Answer
The sag of a transmission line is least affected owing to
A
weight of the conductor
B
current through the conductor
C
atmospheric temperature
D
ice deposited on the conductor
Question 18Single Answer
In case of Impulse Thermal break down of solid insulating materials, the critical electric field is proportional to
A
critical absolute temperature
B
square of critical absolute temperature
C
square of T0
D
none of these
Question 19Single Answer
The insulation of the modern EHV lines is designed based on
A
corona
B
switching voltages
C
lightning voltage
D
all of these
Question 20Single Answer
For constant voltage transmission, the voltage drop along the line is maintained constant by installing
A
capacitors
B
inductors
C
resistors
D
synchronous phase modifiers at the receiving end
Question 21Single Answer
AC network analyser is employed for solving the problems of
A
load flow
B
load flow and stability
C
load flow and short - circuit
D
load flow, stability and short - circuit
Question 22Single Answer
The change in excitation in an alternator connected to an infinite line provides a corresponding change in
A
terminal voltage
B
speed of rotor
C
power generated
D
power factor
Question 23Single Answer
Different types of insulators used for transmission lines are
A
pin type only
B
suspension type only
C
strain type only
D
pin type, suspension type and shackle type
Question 24Single Answer
The conductor connecting consumer's terminals to the distributor is called the
A
feeder
B
distributor
C
service main
D
none of the above
Question 25Single Answer
Which of the following method or techniques can be used for the measurement of high d.c. voltages ?
A
Generating voltmeter
B
Electrostatic voltmeter
C
Peak voltmeter
D
Half effect generators
Question 26Single Answer
The ripple voltage in dc output is small if
A
frequency of supply voltage is small
B
the filtering capacitor is small
C
load current is small
D
none of these
Question 27Single Answer
The voltage measurements using uniform spark gap are
A
affected by dust particles
B
affected by polarity of supply
C
affected by temperature
D
none of these
Question 28Single Answer
Neutral earthing is provided for
A
the safety of personnel from electric shock
B
the safety of equipment and personnel against lightning and voltage surges
C
reducing the voltage stress on lines and equipment with respect to earth under various operating and fault conditions
D
controlling the earth fault currents for protective relaying
E
both (c) and (d)
Question 29Single Answer
The function of Lightning arrester is
A
to limiting the short - circuit fault current
B
to provide path to high voltage surge to earth
C
to reduce arcing
D
none of these
Question 30Single Answer
In which of the following cases are delay fuses used ?
A
For the protection of light circuits
B
For the protection of power out - let circuits
C
For the protection of fluorescent lamps
D
For the protection of motors
Question 31Single Answer
In order to improve the voltage profile of the line, compensation is resorted by providing
A
capacitors at the receiving end
B
reactors at the receiving end
C
resistors at the receiving end
D
none of these
Question 32Single Answer
Skin effect in conductor is proportional to
A
(diameter of conductor) 1/2
B
diameter of conductor
C
(diameter of conductor)2
D
(diameter of conductor)4
Question 33Single Answer
The function of steel wire in an ACSR conductor is to
A
compensate for skin effect
B
take care of surges
C
provide additional mechanical strength
D
reduce inductance
Question 34Single Answer
A fault is more severe from the view point of RRRV if it is a
A
Short length fault
B
Medium length line fault
C
Long length line fault
D
None of these
Question 35Single Answer
Protective resistance to be connected between the sphere gap and the test equipment is required while measuring
A
power frequency and higher frequency a.c. voltage
B
power frequency and impulse voltage
C
all kinds of voltages
D
none of these
Question 36Single Answer
Series capacitor is used in a transmission line to
A
compensate the voltage drop
B
reduce line loss
C
limit short circuit current
D
improve load power factor
Question 37Single Answer
The passive element that is used as interconnecting element for the stable operation of interconnected system is
A
reactor
B
resistor
C
capacitor
D
resistor and capacitor
Question 38Single Answer
Corona loss in a transmission line is dependent on
A
diameter of the conductor
B
material of the conductor
C
height of the conductor
D
none of these
Question 39Single Answer
In a minimum oil circuit breaker the oil is used
A
to act as circuit breaking medium only
B
for circuit breaking and providing insulation
C
for providing insulation only
D
for none of the above purposes
Question 40Single Answer
Skin effect is
A
proportional to frequency
B
proportional to square of frequency
C
inversely proportional to frequency
D
independent of frequency
Question 41Single Answer
Rated making capacity of breaker is equal to
A
X rated symmetrical breaking capacity
B
2.55 X rated symmetrical breaking capacity
C
1 X rated symmetrical breaking capacity
D
none of these
Question 42Single Answer
The main reason for using high voltage for long distance power transmission is
A
reduction in transmission losses
B
reduction in time of transmission
C
increase in system reliability
D
none of the above
Question 43Single Answer
Bus - coupler is very essential in
A
single bus - bar arrangement
B
ring bus - bar arrangement
C
double bus, double breaker arrangement
D
main and transfer bus
Question 44Single Answer
With the rise in temperature, the insulation resistivity
A
remains unchanged
B
decreases linearly
C
increases linearly
D
reduces exponentially
Question 45Single Answer
The effect of bonding the cable is
A
to increase the effective resistance and inductance
B
to increase the effective resistance but reduce inductance
C
to reduce the effective resistance and inductance
D
to reduce the effective resistance but increase the inductance
Question 46Single Answer
Increase in temperature in overhead transmission lines causes
A
increase in stress and length
B
decrease in stress and length
C
decrease in stress but increase in length
D
none of the above
Question 47Single Answer
The insulation resistance of the cable decreases with the
A
increase in length of cable
B
decrease in length of cable
C
electric stresses
D
none of these
Question 48Single Answer
Corona has the disadvantage(s) of
A
power loss
B
interference with neighbouring communication circuits
C
introducing the harmonics, predominately third harmonics, into the transmission lines
D
all of the above
Question 49Single Answer
In a load duration curve for an intergrated power system the uppermost crest represents the energy contributed by
A
base power stations
B
major thermal stations
C
peaking hydro or gas turbine stations
D
non - conventional power stations
Question 50Single Answer
At bridge crossing and near the railway track ternary lead cables are used because they
A
are of high tensile strength
B
are of low coefficient of thermal expansion
C
are of low specific gravity
D
can withstand shocks and vibrations
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Electrical
Question 51Single Answer
The heat produced at the contact point owing to flow of electric current is least affected by
A
temperature of the surrounding medium
B
contact resistance
C
magnitude of electric current flowing
D
duration of flow of current
Question 52Single Answer
A stationary alternator should not be connected to the live bus - bar because
A
it is likely to operate as a synchronous motor
B
it will get short - circuited
C
it will reduce bus - bar voltage
D
all of the above
Question 53Single Answer
In a transmission system the feeder supplies power to
A
transformer substations (step - up)
B
service mains
C
distributors
D
all of the above
Question 54Single Answer
For a given amount of power to be transmitted over a certain distance with fixed power loss, the volume of copper required is
A
directly proportional to voltage
B
inversely proportional to voltage
C
inversely proportional to the square of voltage and pf of the load
D
directly proportional to the square of the voltage and pf of the load
Question 55Single Answer
Power despatch through a line can be increased by
A
installing series capacitors
B
installing shunt capacitors
C
installing series reactor
D
installing shunt reactor
Question 56Single Answer
In the figure shown which curve represents the variation of cost of generation per kWh with the load factor, for a thermal power plant ?
A
Curve A
B
Curve B
C
Curve C
D
Curve D
Question 57Single Answer
Under 'no load conditions the current in a transmission line is because of
A
capacitance effect
B
corona effect
C
proximity effect
D
back flow from earth
Question 58Single Answer
The only advantage of corona is that it
A
produces a pleasing luminous glow
B
makes line current sinusoidal
C
works as a safety valve for surges
D
ozone gas is produced
Question 59Single Answer
Earth wires are made of
A
copper
B
aluminium
C
iron
D
galvanised stranded steel
Question 60Single Answer
The connected load of a consumer is 2 kW and his maximum demand is 1.5 kW. The demand factor of the consumer is
A
0.75
B
0.375
C
1.33
D
none of the above
Question 61Single Answer
A lightning arrester connected between the line and earth in a power system
A
protects the terminal equipment against travelling surges
B
protects the terminal equipment against direct lightning stroke
C
suppresses high frequency oscillations in the line
D
reflects back the travelling waves approaching it
Question 62Single Answer
Oil filled cables have the advantage(s) of
A
smaller overall size
B
most perfect impregnation
C
easy detection of fault
D
all of the above
Question 63Single Answer
A bus coupler circuit breaker is utilised in a substation for
A
joining the transmission line with station bus - bar
B
joining main and transfer bus in a substation
C
joining the generator with transfer
D
joining the neutral of the generator with earth
Question 64Single Answer
The fluids used in circuit breakers should be of
A
high dielectric strength and thermal stability
B
non - inflammability
C
are extinguishing ability
D
all of the above
Question 65Single Answer
Feeder is designed mainly from the point of view of
A
its current carrying capacity
B
voltage drop in it
C
operating voltage
D
operating frequency
Question 66Single Answer
Power output per unit volume of an MHD generator is proportional to
A
specific electrical conductivity of gas
B
square of the magnetic field strength
C
square of the fluid velocity
D
all of the above
Question 67Single Answer
Increase in frequecy of transmission line causes
A
no change in line resistance
B
increase in line resistance
C
decrease in line resistance
D
decrease in line series reactance
Question 68Single Answer
A dc series generator can excite itself
A
only on zero load current
B
only when load current is not zero
C
irrespective of the value of load current
D
none of the above
Question 69Single Answer
Thermal relays are used for protection of motors against over - current owing to
A
short - circuits
B
heavy loads
C
earth fault
D
all of these
Question 70Single Answer
Transmission efficiency of a transmission line increases with the
A
decrease in power factor and voltage
B
increase in power factor and voltage
C
increase in power factor but decrease in voltage
D
increase in voltage but decrease in power factor
Question 71Single Answer
While using air - blast circuit breaker, current chopping is a phenomenon often observed when
A
a long overhead line is switched off
B
a bank of capacitors is switched off
C
a trasformer on no - load is switched off
D
none of these
Question 72Single Answer
The contact resistance of a circuit breaker is about
A
20 Ω
B
2 Ω
C
20 mΩ
D
20 μΩ
Question 73Single Answer
Metallic shielding is provided on underground cables to
A
reduce thermal resistance
B
reduce corona effect
C
control the electrostatic voltage stress
D
all of the above
Question 74Single Answer
The most economical limit of power factor correcting is governed by
A
original power factor
B
relative costs of the supply and power factor correction equipment
C
both (a) and (b)
D
none of the above
Question 75Single Answer
A short - circuit current is identified by
A
heavy current flow
B
voltage rise
C
voltage drop
D
none of these
Question 76Single Answer
Which of the following materials is not used for transmission and distribution of electrical power ?
A
Tungsten
B
Copper
C
Aluminium
D
Cadmium copper
Question 77Single Answer
Which of the following alternators will have maximum number of poles ?
A
Alternator coupled to hydraulic turbine
B
Alternator coupled to steam turbine
C
Alternator coupled to gas turbine
D
All will have same number of poles
Question 78Single Answer
In humid weather, the corona occurs at a voltage
A
much less than the needed in fair weather
B
much higher than that needed in fair weather
C
equal to that needed in fair weather
D
none of the above
Question 79Single Answer
Short - circuit currents are due to
A
single phase to earth fault
B
phase to phase fault
C
all the three phases to earth fault
D
all the three phases short - circuited
E
any of the above
Question 80Single Answer
Over - current protection respond to
A
increase in current above pick - up value
B
single line to earth faults
C
double line to earth faults
D
all of the above
Question 81Single Answer
A fuse is
A
always connected in series with the circuit
B
always connected in parallel with the circuit
C
normally connected in series with the circuit
D
none of these
Question 82Single Answer
Standard impulse testing of power transformer requires
A
one application of chopped wave followed by one application of full - wave
B
two applications of chopped wave followed by an application of a full - wave
C
one application of chopped wave followed by two application of a full - wave
D
none of these
Question 83Single Answer
The presence of earth in case of overhead lines
A
increases the capacitance
B
increases the inductance
C
decreases the capacitance and increases the inductance
D
does not effect any of the line constants
Question 84Single Answer
Partial discharge measurement on a cable gives
A
p.f of the cable
B
loss angle of the cable
C
location of fault
D
None of these
Question 85Single Answer
Any leakage of air into the condenser destroys the vacuum and causes
A
an increase in air pressure in the condenser limiting the useful heat drop in the steam turbine
B
lowering of the partial pressure of the steam and of the saturation temperature along with it
C
undercooling of the condensate more severe
D
all of the above
Question 86Single Answer
The intersheaths in cables are used to
A
provide proper stress distribution
B
minimize the stress
C
provide protection against moisture and voltage surges
D
provide protection against current and voltage surges
Question 87Single Answer
The string efficiency of insulators can be increased by
A
reducing the number of strings
B
increasing the number of strings
C
correct grading of insulators of various strings
D
none of these
Question 88Single Answer
Which one of the following statements regarding the position of minimum copper loss in a phase of rotary convertor is true ?
A
The position of minimum copper loss is in the middle of the phase whatever may be the power factor
B
The position of minimum copper loss varies with the variation in power factor and this position is displaced from the middle of the phase by the power factor angle
C
The position of minimum copper loss is the tapping point whatever may be the power factor
D
None of the above
Question 89Single Answer
In order to have lower cost of electrical generation
A
the load factor and diversity factor should be high
B
the load factor should be low but diversity factor high
C
the load factor should be high but diversity factor low
D
the load factor and diversity factor should be low
Question 90Single Answer
The stability limit of system is defined as the value of power below which
A
the system is stable and above which also stable
B
the system is unstable and above which it is stable
C
the system is stable and above which it is unstable
D
none of these
Question 91Single Answer
Swing equation represents
A
the variation of power with respect to time
B
the variation of torque angle with respect to time
C
the variation of input power with respect to time
D
none of these
Question 92Single Answer
In case of Impulse Thermal breakdown of insulating materials, the critical time to breakdown is
A
proportional to critical electric field
B
inversely proportional to critical electric field
C
proportional to square of critical absolute temperature
D
none of these
Question 93Single Answer
Economiser in a steam power plant
A
improves the boiler efficiency by 10 - 12 %
B
saves fuel consumption by 5 - 15 %
C
becomes a necessity for pressure
D
none of these
Question 94Single Answer
Conductor configuration determine
A
inductance
B
sag
C
voltage
D
current
Question 95Single Answer
If the length of the arc of circuit breaker increases, its resistance
A
be extinguished
B
decreases
C
remains same
D
none of these
Question 96Single Answer
If the frequency of a transmission system is changed from 50 Hz to 100 Hz, the string efficiency
A
will increase
B
will decrease
C
remain unchanged
D
may increase or decrease depending on the line parameters
Question 97Single Answer
The pressurised water reactors employ
A
light water and natural uranium
B
heavy water and enriched uranium
C
light water and enriched uranium
D
none of the above combinations
Question 98Single Answer
The suitable turbine used for harnessing tidal power is
A
Francis turbine
B
Pelton turbine
C
Kaplan turbine
D
None of these
Question 99Single Answer
In an AC Transmission line, difference in phase of voltages at the two ends of the line is due to
A
resistance of line
B
system voltage
C
reactance of line
D
insulators
Question 100Single Answer
Steam power plants work closely on
A
Binary vapour cycle
B
Brayton cycle
C
Rankine cycle
D
Carnot cycle
Question 101Single Answer
If the tariff for electrical energy charges provides incentive by way of reduced charges for higher consumption, then it may be concluded that the
A
load factor is high
B
power factor is high
C
plant has sufficient reserve capacity
D
power is generated through hydro - power plant
Question 102Single Answer
In overhead lines, the presence of earth wire causes
A
increase in the capacitance
B
increase in the inductance
C
decrease in the capacitance
D
decrease in the inductance
Question 103Single Answer
The use of reactors permits circuit breakers of the installation of
A
lower rating
B
higher rating
C
same rating
D
none of these
Question 104Single Answer
In power plants, the condenser normally used is
A
Surface type
B
Jet type
C
Both surface and jet type
D
Regenerative type
Question 105Single Answer
The critical mass of a nuclear reactor depends upon
A
the enrichment of the fuel used
B
the moderator material used
C
both the enrichment of fuel and moderator material
D
none of these
Question 106Single Answer
When the load on a transmission line is equal to the surge impedance loading
A
the receiving end voltage is less than the sending end voltage
B
the sending end voltage is less than the receiving end voltage
C
the receiving end voltage is equal to the sending end voltage
D
none of these
Question 107Single Answer
In a power plant, a reserve generating capacity which is not in service but is in operation is known as
A
hot reserve reserve
B
cold
C
firm power
D
spinning reserve
Question 108Single Answer
What is the advantage of hydro - electric power stations over thermal power stations ?
A
The initial cost of hydro - electric power stations is low .
B
Their operating cost is low .
C
Hydro - electric power stations can supply the same power throughout the year .
D
Hydro - electric power stations can be constructed where electric energy is required .
Question 109Single Answer
Galvanised steel wire is usually used as
A
stay wire
B
earth wire
C
structural components
D
all of the above
Question 110Single Answer
It is always economical to improve the p.f. of an installation to
A
zero
B
unity
C
a little less than unity
D
a little more than unity
Question 111Single Answer
The efficiency of a transmission line
A
increases with the decrease in load p.f.
B
is independent of load p.f.
C
increases with the increase in load p.f.
D
decreases with the increase in load p.f.
Question 112Single Answer
If the source is not able to supply charging current required by the test cable, it is desirable to use
A
shunt capacitor
B
series capacitor
C
series inductor
D
none of these
Question 113Single Answer
Isolated neutral transmission system is not recommended as the
A
system insulation is overstressed due to over - voltages
B
insulation overstress may lead to its failure resulting in phase to phase faults
C
system is not adequately protected against earth fault
D
all of the above
Question 114Single Answer
The power loss in an overload transmission line is mainly due
A
impedance of the line conductor
B
resistance of each conductor
C
inductance of each conductor
D
capacitance of each conductor
Question 115Single Answer
Sulphur hexafluoride cable is insulated by
A
impregnated paper
B
polyvinyl chloride
C
high pressure oil
D
compressed gas
Question 116Single Answer
The voltage of a bus can be controlled by controlling the
A
phase angle
B
reactive power of the bus
C
active power of the bus
D
phase angle and the reactive power
Question 117Single Answer
A three phase breaker is rated at 2000 MV A, 33 kV, its making current will be
A
35 kA
B
70 kA
C
89 kA
D
160 kA
Question 118Single Answer
The insulation used in a cable designed for use on 1000 kV is usually
A
impregnated paper
B
compressed SF, gas
C
PVC
D
any of the above
Question 119Single Answer
The main function of under voltage protective device generally employed with a motor starter is to power
A
open the supply circuit on failure of supply
B
control the motor voltage
C
prevent the opening of supply circuit
D
none of the above
Question 120Single Answer
Which of the following power plants is free from environmental problems ?
A
Diesel engine
B
Nuclear
C
Hydro - electric
D
Steam
Question 121Single Answer
Which of the following is not a secondary nuclear fuel ?
A
Pu239
B
U233
C
U235
D
None of above
Question 122Single Answer
The purpose of the moderator in a nuclear power plant is to water inlet
A
control the flow of
B
control the amount of nuclear fuel into the reactor
C
control the nuclear fission or fission rate by slowing down the neutrons
D
control the steam flow to the turbine
Question 123Single Answer
Rotating machines are protected against lightning surges by a combination of
A
lightning conductor and capacitor
B
lightning conductor and lightning arrester
C
lightning arrester and capacitor
D
none of these
Question 124Single Answer
The gas turbine power plant can be used in combination with steam power plants by
A
using exhaust gases from gas turbine power plant in heating of feed water coming from the steam trubine condenser
B
using exhaust gases from gas turbine power plant as combustion air in steam boiler
C
using gas from a supercharged boiler for expansion in gas turbine
D
any of the above
Question 125Single Answer
Skin effect
A
increases the effective resistance and effective internal reactance
B
reduces the effective resistance and effective internal reactance
C
increases the effective resistance but reduces the effective internal reactance
D
reduces the effective resistance but increases the effective internal reactance
Question 126Single Answer
The critical clearing time is related to
A
steady state stability limit
B
transient stability limit
C
short - circuit current limit
D
none of these
Question 127Single Answer
As compared to air the relative dielectric strength of sulphur hexafluoride is nearly
A
1.5 times
B
2.5 times
C
4.0 times
D
5.0 times
Question 128Single Answer
The relay best suited for phase fault relaying for medium transmission lines is
A
mho relay
B
reactance relay
C
impedance relay
D
none of these
Question 129Single Answer
In parallel operation of alternators, the synchronising power will be maximum when
A
armatures have resistances equal to their reactances
B
armatures have resistances more than their reactances
C
armatures have resistances lesser than their reactances
D
none of the above
Question 130Single Answer
An adjustable blade propeller turbine is called a
A
Pelton turbine
B
Kaplan turbine
C
Francis turbine
D
None of them
Question 131Single Answer
The criterion for selection of size of conductor for a feeder is
A
Voltage drop
B
Corona loss
C
Temperature rise
D
Radio interference
Question 132Single Answer
Inverse time - current protection of relays are used for the
A
feeders
B
transformers
C
alternators
D
both (a) and (b)
Question 133Single Answer
Surge voltage originate in power system due to
A
lightening
B
switching operations
C
faults
D
all of these
Question 134Single Answer
The proximate analysis of coal gives percentage by weight of
A
moisture and volatile matter
B
moisture, volatile matter, fixed carbon and ash
C
carbon, hydrogen, oxygen, nitrogen, sulphur and ash
D
carbon, hydrogen and oxygen
Question 135Single Answer
A gas turbine works on
A
Carnot cycle
B
Brayton cycle
C
Dual cycle
D
Rankine cycle
E
Regenerative cycle
Question 136Single Answer
Which of the following protects the underground cables against mechanical injury ?
A
Armouring
B
Bedding
C
Sheath
D
None of these
Question 137Single Answer
Coal and peat is not generally used in gas turbines as fuel because of
A
coal handling and ash handling problems
B
their higher costs
C
their non - availability
D
all of the above
Question 138Single Answer
A 1000 kVA transformer with 5% reactance will have a reactance of 10% at
A
1000 kVA base
B
2000 kVA base
C
3000 kVA base
D
4000 kVA base
Question 139Single Answer
In circuit breakers the contact space is ionized by
A
field emission from the contact surface
B
thermal emission from the contact surface
C
thermal ionization of gas
D
any of the above
Question 140Single Answer
When extra stop buttons are added to an existing starter control circuit they must be
A
in series with the contactor coil
B
parallel to the overload
C
parallel to the start button
D
in series with the motor
Question 141Single Answer
In a transmission line, if the load is suddenly increased in the receiving end of the system, the phase shift will
A
decrease
B
become zero
C
increase
D
not be affected
Question 142Single Answer
In case of inter - connected system for stable operation the passive element that can be used as interconnecting element is
A
capacitor
B
reactor
C
resistor
D
any of these
Question 143Single Answer
The rate of rise of restriking voltage depends upon
A
the type of Circuit Breaker
B
the inductance of the system only
C
the capacitance of the system only
D
the inductance and capacitance of the system
Question 144Single Answer
To increase the transmission capability of a high voltage long line
A
the resistance can be increased
B
the resistance can be decreased
C
the series reactance can be reduced
D
the shunt admittance can be reduced
Question 145Single Answer
In Van de Graff generator, output voltage is controlled by
A
controlling the corona source voltage
B
controlling the belt speed
C
controlling the lower spray point
D
all of these
Question 146Single Answer
In a dc 3 - wire distributor using balancers and having unequal loads on the two sides
A
both balancers operate as generators
B
both balancers operate as motors
C
balancer connected to lightly loaded side operates as a generator
D
balancer connected to heavily loaded side operates as a generator
Question 147Single Answer
In context of corona which statement is not true ?
A
Corona is voltage effect .
B
Corona takes place on short transmission lines .
C
Corona is accompanied with power loss .
D
Corona attenuates lightning surges .
Question 148Single Answer
The frequency of voltage generated can be increased by
A
adjusting the governor
B
increasing the excitation
C
reducing the excitation
D
any of the above
Question 149Single Answer
The advantage of transmitting power at high voltage is
A
magnitude of current will be small
B
it will reduce the voltage drop in the line impedance
C
power loss will be less
D
all of these
Question 150Single Answer
If the height of the transmission tower is changed, which of the following parameters is likely to change ?
X rated symmetrical breaking capacity