AP ECET 2021 (EEE) Question Paper with Answers

1/100
The demagnetizing component of armature reaction in a DC generator
A) Reduces generated emf
B) Increases armature speed
C) Reduces interpoles flux density
D) Results in sparking trouble
2/100
A 4 pole, lap wound d.c. generator has 40 coils with 8 turns per coil. It is driven at 1200 rpm. If the flux per pole is 0.022 Wb, then the generated emf is
A) 265.8 V
B) 276.3 V
C) 281.6 V
D) 287.9 V
3/100
In Fleming's right hand rule, the direction of the induced emf in the conductor is given by
A) Index finger
B) Middle finger
C) Thumb
D) Ring finger
4/100
The armature reaction effect in d.c. machines can be neutralized by using C
A) Only compensating winding
B) Only interpoles
C) Both compensating winding and interpoles
D) Main field winding
5/100
Which of the following motor is having very high no load speed?
A) DC shunt motor
B) DC series motor
C) DC compound motor
D) Induction motor
6/100
If a shunt motor is started with its field winding open then
A) It will rotate at the same speed as that with its field winding closed
B) It will rotate at less speed as that with its field winding closed
C) It will rotate at dangerously high speed
D) It will not rotate
7/100
If a resistance is added in series with the field winding of d.c. shunt motor. then its
A) Both speed and torque decreases
B) Both speed and torque increases
C) Speed decreases, torque increases
D) Speed increases, torque decreases
8/100
A 220 V, d.c. motor draws an armature current of 20 A. Its armature resistance is 0.6 ohm. Then the back emf in the motor will be
A) 195 V
B) 202 V
C) 208 V
D) 215 V
9/100
The main purpose of performing short circuit test on a transformer is to measure its
A) Copper loss
B) Core loss
C) Insulation resistance
D) Total loss
10/100
The essential condition for parallel operation of two single-phase transformers is that they should have the same
A) KVA Rating
B) Turn Ratio
C) Size
D) Polarity and Turn Ratio
11/100
Which of the following loss in a transformer is zero even at full load?
A) Eddy current loss
B) Core loss
C) Copper loss
D) Friction loss
12/100
The size of the transformer core mainly depends on
A) Air gap
B) Area of core
C) Flux density of core
D) Frequency and area of core
13/100
Open delta transformers can be obtained from
A) Delta-delta
B) Star-delta
C) Delta-star
D) Only Star
14/100
What are the modes in which power can be transferred in an autotransformer?
A) Conduction and intension
B) Induction and intension
C) Conduction and Induction
D) Cannot be said
15/100
In a transformer the resistance between its primary and secondary i y is
A) Zero
B) Infinite
C) 1000 ohm
D) 100 ohm
16/100
Alternator on infinite bus bar has constant
A) Terminal voltage and frequency
B) Frequency
C) Power factor
D) Power factor and terminal voltage
17/100
The rating of the alternator is decided by
A) Losses
B) Voltage
C) Armature Current
D) Temperature
18/100
The short circuit characteristic of alternator is a straight line due to
A) No saturation
B) No armature reaction
C) No eddy current
D) No hysteris loss
19/100
WHAT HAPPENS IF FIELDS WINDING OF THE SYNCHRONOUS moter is short circuited ?
a) First, it starts as induction motor then run as synchronous motor
b) It will not start
c) Motor will burn out
d) It runs as induction motor
20/100
The armature current of the synchronous motor has large values for
a) High excitation
b) Unity power factor
c) Both high and low excitation 3.V
d) Only at low excitation
21/100
The damper winding in a synchronous motor is provided for
A) Starting torque only
B) Reducing eddy currents
C) Preventing hunting and providing the starting torque
D) Reducing the noise level
22/100
If autotransformer method of starting is used to start an induction motor to replace star-delta method, then the required tapping on the transformer will be ________
A) 57.73%
B) 86.7%
C) 57%
D) 66.66%
23/100
Three phase supply is fed to the Induction motor and is running at its normal operating conditions. Then the synchronous speed can be defined as speed at which?
A) Stator magnetic field rotates
B) Rotor magnetic field rotates
C) Rotor rotates
D) Slip speed
24/100
A 4 pole three phase induction motor having synchronous speed of 1500 rpm is operating at 1450rpm. The frequency of the induced emf in rotor is?
A) 1.667 Hz
B) 16.667 Hz
C) 0.1667 Hz
D) 166.667 Hz
25/100
In a 3-phase slip ring induction motor high starting torque is achieved by
A) Increasing supply voltage
B) Increasing supply frequency
C) Connecting a capacitor across the motor terminals
D) CONNECTING a star conected resistance across slip ring terminal of motor
26/100
In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to
a) Improve power factor
b) Reduce fluctuations in torque
c) Increase overload capacity
d) To improve torque
27/100
In split-phase motor, the main winding is made up of
a) Thick wire placed at the top of the slots
b) Thick wire placed at the bottom of the slots
c) Thin wire placed at the top of the slots
d) Thin wire placed at the bottom of the slots
28/100
The power factor of a single phase load can be calculated if the instruments available are
a) One voltmeter and one ammeter
b) One voltmeter, one ammeter and one wattmeter
c) One voltmeter, one ammeter and one energy meter
d) Only wattmeter
29/100
In a single phase power factor meter the phase difference between the currents in the two pressure coils is
a) Exactly 0°
b) Approximately 0°
c) Exactly 90°
d) Approximately 90°
30/100
The disc of an instrument using eddy current damping should be made of
a) Conducting and magnetic material
b) Non-conducting and magnetic material
c) Conducting and nonmagnetic material
d) Only conducting material
31/100
If damping torque is not provided in an instrument
a) An instrument will show full wave of quantity even under small values
b) The pointer will move only when full rated load is provided
c) The pointer will oscillate about its final deflected position and will never come to rest even under steady conditions
d) The pointer will oscillate about its final deflected position for quite some time before coming to rest
32/100
What should be the height of the 'Roof Pole"?
a) 3m
b) Less than 3m
c) More than 3m
d) Cannot be decided
33/100
Earthing is necessary to give protection against
a) Danger of electric shock
b) Voltage fluctuation
c) Overloading
d) High temperature of the conductors
34/100
The earthing rod orientation in the pit should be:
a) 45°
b) Horizontal
c) Vertical
d) 75°
35/100
What is the cause for mechanical overloads in the induction motors?
a) Stalling
b) Blowing of fuse
c) Under voltage
d) Open circuit
36/100
Locomotives with monometer bogies have
a) Uneven distribution of tractive effect
b) Suitability for passenger as well freight service
c) lot of skidding
d) Low coefficient of adhesion
37/100
Specific energy consumption is least in _________ service.
a) Main line
b) Urban
c) Suburban
d) Rural service only
38/100
The coasting retardation is around
a) 16 km phps
b) 1.6 km phps
c) 0.16 km phps
d) 40 km phps
39/100
Overhead lines for power supply to tram cars are at a minimum height of
a) 3 m
b) 6m
c) 10 m
d) 15 m
40/100
The rate of acceleration on suburban or urban services is restricted by the consideration of
a) Engine power
b) Track curves
c) Passenger discomfort
d) Track size
41/100
Which of the following is the advantage of electric braking?
a) It is instantaneous
b) Motor continues to remain loaded during braking
c) It avoids wear of track
d) More heat is generated during braking
42/100
The value of coefficient of adhesion will be high when rails are
a) Greased
b) Cleaned with sand
c) Sprayed with oil
d) Wet
43/100
Which of the following is the disadvantage of electric traction over other systems of traction?
a) Corrosion problems in the underground pipe work
b) Short time power failure interrupts traffic for hours
c) High Capital outlay in fixed installations beside route limitation
d) Interference with communication lines
44/100
With regards to measuring current and voltage in an AC circuit, modern AC instruments are calibrated to read:
a) RMS values
b) Peak values
c) Average values
d) Form factor values
45/100
The current waveform for a purely resistive circuit:
a) Leads the voltage by 90°
b) Is in phase with the voltage
c) Lags the voltage by 90°
d) Alternately leads and lags the voltage
46/100
When two capacitors are connected in series, the total capacitance:
a) Is double the capacitance of any one
b) Is decreased
c) Is increased
d) Remains the same as the largest one
47/100
The power factor of an AC circuit can be found using the formula, Power factor =
a) Volt-amperes/watts
b) Volt-amperes x current
c) Watts/volt-amperes
d) Volts x volt-amperes
48/100
the reactive power can be mesured with wattmeter when voltage across voltage coil is adjusted to be out of phase with the current by
a) 90°
b) 180°
c) 45°
d) 0°
49/100
The 8051 microcontroller is _____ of pin package as a _______ processor.
a) 30, 1byte
b) 20. 1 byte
c) 40, 8 bit
d) 40, 8 byte
50/100
What is the address range of SFR Register bank?
a) 00H-77H
b) 40H-80H
c) 80H-7FH
d) 80H-FFH
51/100
Serial port interrupt is generated, if _______ bits are set
a) IE
b) RI, IE
c) IP. TI
d) RI. TI
52/100
In 8051 which interrupt has highest priority?
a) IΕ1
B) TFO
C) IEO
D) TF1
53/100
The condition for the validity of Ohm's law is that the
A) Temperature should remain constant
B) Current should be proportional to voltage
C) Resistance must be wire wound type
D) Resistance must be varying type
54/100
Property of a material which opposes the production of magnetic flux in it is called
A) MMF
B) Reluctance
C) Permeance
D) Permittivity
55/100
Resistance of the conductor is doubled keeping the potential difference across it constant. The rate of generation of heat will be
A) Be halved
B) Becomes four times
C) Become one fourth
D) Be doubled
56/100
Which of the following statement is not correct about the magnetic field?
A) Magnetic field lines form a continuous closed curve.
B) Magnetic field line do not intersect each other.
C) Direction of tangent at any point on the magnetic field line curve gives the a direction of magnetic field at that point.
D) Outside the magnet, magnetic field lines go from South to North pole of the magnet.
57/100
What happens to the force acting between the charged particles, if the distance between them is halved?
A) It increases by four times
B) It gets doubled
C) It becomes half
D) It reduces by one-fourth
58/100
Which of the following is a semiconductor material?
A) Phosphorous
B) Rubber
C) Silicon
D) Aluminium
59/100
Which of the following circuit element is an active component?
A) Capacitor
B) Transistor
C) Inductor
D) Resistor
60/100
Which of the following generation station has minimum running cost?
A) Thermal power station
B) Hydro-electric power station
C) Nuclear power station
D) Gas based power station
61/100
Economiser is used to heat
A) Air
B) Feed water
C) Flue Gases
D) Smoke
62/100
Kaplan turbine is used for...................hydro-electric plant
A) Medium and low head
B) High head
C) Low head
D) Low and high head
63/100
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
D) To produce varying pressure
64/100
When muclear reactor is operating at constant power, the multiplication factor is........
A) Equal to unity
B) More than unity
C) Less than unity
D) Zero
65/100
The most appropriate operating speeds in rpm of generators used in Thermal. Nuclear and Hydro-power plants would respectively be
A) 3000, 300 and 1500
B) 3000, 3000 and 300
C) 1500, 1500 and 3000
D) 1000, 900 and 750
66/100
To limit current chopping in vacuum circuit breakers, the contact material used has:
A) High vapour pressure and low conductivity properties
B) High vapour pressure and high conductivity properties
C) Low vapour pressure and high conductivity properties
D) Low vapour pressure and low conductivity properties
67/100
A Mho relay is a
A) Voltage restrained directional relay
B) Voltage controlled over current relay
C) Directional restrained over current relay
D) Directional restrained over voltage relay
68/100
The normal practice to specify the making current of a circuit breaker is in terms of
A) R.M.S value
B) Peak value
C) Average value
D) Form factor
69/100
Auto reclosing is used in case of
A) Lightning arrester
B) Air blast Circuit Breaker
C) Bulk oil Circuit Breaker
D) Minimum oil Circuit Breaker
70/100
Ring main distribution preferred to a radial system because
A) Voltage drop in the feeder is less and supply is more reliable
B) Voltage drop in the feeder is less and power factor is high
C) Power factor is high and supply is more reliable
D) POWER FACTOR IS HIGH supply is more reliable
71/100
The good effect of corona on overhead lines is to
A) Increase the line carrying capacity due to conducting ionised air enveloP around the conductor
B) Increase the power factor due to corona loss
C) Reduce the radio interference from the conductor
D) Reduce the steepness of surge fronts.
72/100
The values of A. B. C and D constants for a short transmission line are respectively
A) Z. 0.1 and 1
B) 0, 1, 1 and 1
C) 1. Z. 0 and 1
D) 1. 1. Z and 0.
73/100
Between two supports, due to sag the conductor takes the form of
A) Catenary
B) Triangle
C) Ellipse
D) Semi-circle
74/100
Whenever the conductors are dead-ended or there is a change in the directioN of transmission line, the insulators used are of the
A) Pin type
B) Suspension type
C) Strain type
D) Shackle type
75/100
Transmission lines are transposed to
A) Reduce copper loss
B) Reduce skin effect
C) Prevent interference with neighbouring telephone lines
D) prevent short-circuit between any two lines
76/100
The voltages across various discs of suspension insulators having identical discs is different due to
A) Surface leakage currents
B) Series capacitance
C) Shunt capacitances to ground
D) Series and shunt capacitances.
77/100
Sheaths are used in cables to:
A) Provide proper insulation
B) Provide mechanical strength
C) Prevent ingress of moisture
D) Prevent current
78/100
Stringing chart is useful for:
A) Finding the sag in the conductor
B) In the design of tower
C) In the design of insulator string
D) Finding the distance between the tower
79/100
Charging current in medium transmission line is
A) Maximum at receiving end
B) Maximum at sending end
C) More in between sending end and receiving end
D) Equal throughout the line
80/100
A PN junction acts as a
A) Controlled switch
B) Bidirectional switch
C) Unidirectional switch
D) Open circuit
81/100
Zener diode can be described as
A) A rectifier diode
B) A device with constant - voltage
C) A device with constant-current
D) A device that works in the forward region
82/100
A 4-variable AND-OR circuit produces a 1 at its Y output Which combination of inputs is correct?
A) A=0. B = 0.C = 0, D = 0
B) A = 0, B = 1 C=1. D = 0
C) A = 1 ,B=1,C=0,D=0
D) A = 1 ,B=0,C=0,D=0
83/100
What type of logic circuit is represented by the figure shown below?
A) XOR
B) XNOR
C) XAND
D) XNAND
84/100
Which of the following expressions is in the sum-of-products form?
A) (A+B)(C+D)
B) (AB)(CD)
C) AB(CD)
D) AB+CD
85/100
What is the binary subtraction of 101001-010110=?
A) 010011
B) 100110
C) 011001
D) 010010
86/100
Oscillators are used to _______ AC voltage.
A) Prevent
B) Generate
C) Amplify
D) Rectify
87/100
The output of oscillator will not depend upon
A) Feedback
B) Amplifier
C) Both feedback and amplifier
D) Input voltage
88/100
The use of amplifier in a circuit is to _________ for input signal.
A) Provide a phase shift
B) Provide strength
C) Provide frequency enhancement
D) Make circuit compatible
89/100
DC average current of a centre taped full wave rectifier is (Where In is the maximum peak current of input)
A) 21m/Π
B) Im Π
C) I 2Π
D) 1.4141m/Π
90/100
For a NPN bipolar transistor, what is the main stream of current in the base region?
A) Drift of holes
B) Diffusion of holes
C) Drift of electrons
D) Diffusion of electrons
91/100
A thyristor can be brought from the forward conduction mode to forward blocking mode by
A) The dv/dt triggering method
B) Applying a negative gate signal
C) Applying a positive gate signal
D) Applying a reverse voltage across anode-cathode terminals
92/100
di/dt protection is provided to the thryistor by
A) Connecting an inductor in parallel across the load
B) Connecting an inductor in series with the load
C) Connecting an inductor in parallel across the gate terminal
D) Connecting an inductor in series with the gate
93/100
SCRs are connected in parallel to fulfill the ______ demand
A) High voltage
B) High current
C) Size
D) Efficiency
94/100
The GTO can be turned off
A) by a positive gate pulse
B) by a negative gate pulse
C) by a negative anode-cathode voltage
D) by removing the gate pulse
95/100
A single phase full-converter using R load is a _________ quadrant converter and that using an RL load without FD is a ________ quadrant converter
A) One, one
B) Two, one
C) One, two
D) Two, two
96/100
A chopper may be thought as a
A) An inverter with DC input
B) A DC equivalent of an AC transformer
C) A diode rectifier
D) A DC equivalent of an induction motor
97/100
In case of the 120 mode of operation _______ devices conduct at a time
A) 2
B) 3
C) 4
D) 6
98/100
Which one of the following is the main advantage of the SMPS over linear power supply?
A) No transformer is required
B) Only one stage of conversion
C) No filter is required
D) Low power dissipation
99/100
_______ is used for critical loads where temporary power failure can cause a great deal of inconvenience
A) SMPS
B) UPS
C) MPS
D) RCCB
100/100
In order to prevent distortion in the output signal after amplification, the input signal must be
A) Be higher than the positive saturation level of the amplifier
B) Be lower than the negative saturation level of the amplifier
C) Lie with the negative and the positive saturation level of the amplifier
D) Be both higher than the positive saturation level of the amplifier and lower than the negative Saturation level of the amplifire saturation level of the amplifier
Result:
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