AP ECET 2020 (EEE) Question Paper with Answers

1/100
Which of the following statement is not correct?
A) ohm's law is applicable to ohmic conductors only
B) KCL is derived from law of conservation of charges
C) superposition theorem is applicable to a circuit to calculate power
D) hevenin's voltage (V_th) is an open circuit voltage across the load terminals
2/100
Two wires are made up of same mass of copper material with 2 mm and 3 mm thick. The two wires are connected in series across a constant supply. Heat produced in the wires is in the ratio of
A) 81:16
B) 9:4
C) 2:3
D) 27.8
3/100
Consider the following circuit. The current in 5 ohms resistor is
A) -1 A
B) 2 A
C) 1A
D) circuit does not exist
4/100
The efficiency of nickel-iron cell is less than the lead acid cell due to
A) smaller quantity of electrolyte used
B) lower emf
C) Higher internal resistance
D) compactness
5/100
The current flowing through a 2 cm long coil of 10 tums is 750 mA. The magnetizing force in AT/ m is
A) 350
B) 375
C) 1500
D) 750
6/100
Which of the following insulating material has affinity to moisture
A) Bakelite
B) porcelain
C) glass
D) asbestos
7/100
Find the source voltage, if the voltage between CD in the following circuit is 5 V.
A) 15V
B) 25V
C) 35V
D) 16V
8/100
If the number of conductors and speed of a Lap wound D.C. Generator is doubled then the generated e.m.f will be --------
A) Remains the same
B) Double the former value
C) Eight times the former value
D) Four times the former value
9/100
Copper brushes in D.C. machine are used
A) where low voltage and high currents are involved
B) where high voltage and small currents are involved
C) Where low voltage and low currents are involved
D) Where high voltage and high currents are involved
10/100
The em.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm If the armature current is 200 A, the terminal voltage will be
A) 640 V
B) 620 V
C) 600 V
D) 580 V
11/100
Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced em.f's of generator A and B will be
A) 2:3
B) 3:1
C) 3.2
D) 1:3
12/100
A D.C. series motor is that which
A) has its field winding consisting of thick wire and less turns
B) has a poor torque 2.
C) can be started easily without load
D) has almost constant speed
13/100
In case of D.C. shunt motors the speed is dependent on back e.m.f. only because
A) back e.m.f. is equal to armature drop
B) armature drop is negligible
C) flux is proportional to armature current
D) flux is practically constant in D.C. shunt motors
14/100
In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to
A) 100% of the previous value
B) 25% of the previous value
C) 50% of the previous value
D) 10% of the previous value
15/100
Which of the following method of speed control of D.C. machine will offer minimum efficiency?
A) Voltage control method
B) Field control method
C) Armature control method.
D) Ward-Leonard method
16/100
Which of the following are integrating instruments?
A) Ammeters
B) Voltmeters
C) Wattmeters
D) ampere-hour and watt-hour meters
17/100
For handling greater currents induction wattmeter are used in conjunction with
A) Potential transformers
B) current transformers
C) power transformers
D) Resistors
18/100
The output of thermocouple is in the range of
A) Volts
B) Millivolts
C) Amperes
D) Milliamperes
19/100
The temperature coefficient of thermistor transducer is
A) Negative
B) Positive
C) Zero
D) Infinite
20/100
In an AC circuit (sine wave) with R and L in series Options:
A) Voltage across R and L 180° out of face
B) the voltage across R lags the voltage across L by 90°
C) the voltage across R leads the voltage across L by 90º
D) voltage across R and L are in phase
21/100
A parallel AC circuit in resonance will
A) Have a high voltage developed across each inductive and capacitive section
B) Have high impedance
C) Act like a resistor of low value
D) Have current in each section equal to the line current
22/100
In an RL series circuit R-10 Ω and XL=17.32 Ω. The phase angle in degrees between voltage and current is
A) 30
B) 45
C) 60
D) 90
23/100
A three phase, balanced delta connected load of 25<-63.4° Ω is connected across a 400V. 3-0 balanced supply Determine the phase current IR. (Assume phase sequence to be RYB)
A) 15<-63.4°A
B) 25<63.4° A
C) 25<-63.4°A
D) 16<63.4° A
24/100
By using two wattmeter method. power can be measured in
A) 3-phase. 3-wire system
B) 3-phase, 2-wire system
C) 3-phase, 4-wire system
D) 1-phase. 2-wire system
25/100
The purpose of providing iron core is to
A) Provide support to windings
B) Reduce hysterisis loss
C) Decrease reluctance of magnetic path
D) Reduce eddy current loss
26/100
A good voltage regulation of a transformer means
A) Difference between primary and secondary voltages is more
B) output voltage fluctuation from no load to full load is least
C) Output voltage fluctuation with power factor is least
D) Difference between primary and secondary voltages is least
27/100
The useful flux of a 1-Φ transformer at full load is 2 webers. At half load, the flux will be
A) 0.5 webers
B) 1 weber
C) 4 webers
D) 2 webers
28/100
Why Transformers connected in parallel should have same voltage ratio?
A) To avoid no load circulating current
B) To avoid full load circulating current
C) To avoid other losses
D) To avoid all types of currents
29/100
Breather is provided in a transformer to
A) Absorb moisture of air during breathing
B) the filter of transformer oil
C) provide cold air in the transformer
D) insulation between windings
30/100
The efficiency of two identical transformers under load conditions can be determined by
A) Short Circuit test
B) open Circuit test
C) No Load test
D) back to Back test
31/100
When a two-winding transformer is connected as an auto-transformer, its efficiency
A) Raises to 100%
B) Increases
C) Remains the same
D) Decreases
32/100
The main disadvantage of using short-pitch winding in alternators is that it
A) Reduces harmonics in the generated voltage
B) Reduces the total voltage around the armature coils
C) produces asymmetry in the three phase windings
D) increases Cu of end connections
33/100
The full load terminal voltage of an alternator is greater than no load terminal voltage when
A) load is highly inducted
B) alternator is under excitation
C) load is highly capacitive
D) input mechanical power is increased
34/100
If two alternators are running in parallel and the excitation of one of the alternators is increased, then
A) Power output will decrease
B) Wattless component will change
C) Both machines will start vibrating
D) Machine with excess excitation will burn
35/100
If the field of a synchronous motor is under excited, the power factor will be
A) Lagging
B) unity
C) leading
D) >1
36/100
A synchronous motor working at leading power factor can be used as
A) Voltage booster
B) Noise generator
C) Mechanical synchronizer
D) phase advancer
37/100
The effect of increasing load on a synchronous motor running with normal excitation is to
A) increase both its Iₐ and p.f.
B) Decrease Iₐ but increase p.f.
C) Increase Iₐ but decrease p.f
D) Decrease both its Iₐ and p.f
38/100
In squirrel cage induction motors, the rotor slots are given slight skew in order to
A) reduce windage losses
B) reduce eddy currents 2.
C) reduce accumulation of dirt and dust
D) reduce magnetic hum
39/100
A wound rotor induction motor runs with a slip of 0.03 when developing full load torque. Its rotor resistance is 0.25 ohms per phase. If an external resistance of 0.5 ohm per phase is connected across the slip rings, what is the slip for full load torque?
A) 0.03
B) 0.06
C) 0.09
D) 0.1
40/100
Star-delta starting of motors is not possible in case of
A) single phase motors
B) variable speed motors
C) low horse power motors
D) high speed motors
41/100
In case of a double cage induction motor, the inner cage has
A) high inductance and low resistance
B) low inductance and high resistance
C) low inductance and low resistance
D) high inductance and high resistance
42/100
A single phase induction motor is not self starting because it has
A) no slip
B) Absence of rotating magnetic field
C) High inertia
D) Rotor is short circuited
43/100
Which of the following will have a better power factor?
A) Capacitor start
B) Shaded pole
C) Split phase
D) Capacitor run
44/100
The effect of water hammer can be minimized by using
A) Anvil
B) Spill way
C) Surge tank
D) Draft tube
45/100
If load factor and diversity factor increases, the cost of units generated
A) decreases
B) Increases
C) Remains same
D) insufficient data
46/100
In ------ tariff the total energy consumed is divided into blocks.
A) Flat rate
B) Block rate
C) Two part
D) Maximum demand
47/100
The shielding of nuclear reactor is made of
A) Heavy water
B) Uranium
C) Cadmium
D) cement concrete
48/100
One of the drawbacks of low power factor is
A) Decreases number of units consumed
B) Decreases the efficiency of the system
C) Improvement in voltage regulation
D) Reduction in overall cost per unit
49/100
Mho relay is normally used for protection of
A) Short transmission lines
B) Medium transmission lines
C) Long transmission lines
D) No length Criterion
50/100
------- relay is an instantaneous relay
. A) Induction disc type
B) Balanced beam type
C) Hinged armature type
D) polarized type
51/100
For protection of parallel feeders fed at one end, the relays required are
A) . Directional relays at both ends
B) Non-directional relays at both ends
C) Non-directional relay at source end and directional relay at load end
D) Directional relay at source end and non-directional relay at load end
52/100
The transient voltage that appears across the contacts at the instant of are extinction is called
A) supply voltage
B) peak voltage
C) recovery voltage
D) re-striking voltage
53/100
In a lightning arrester impedance path exists between the line and ground
A) Infinite, always
B) low, before the over voltage
C) High, before the over voltage
D) low, at the instant of over voltage
54/100
If the spacing berween the conductors of a line is increased, the inductance -------- and the Capacitance --------
A) Increases. decreases
B) Increases, increases
C) Decreases, decreases
D) Decreases, increases
55/100
Under no-load condition, the current in a transmission line is due to
A) Corona effect
B) Inductance of the line
C) Capacitance of the line
D) back flow from the earth
56/100
Corona loss increases with
A) Increase in conductor size and decrease in supply frequency
B) . Decrease in conductor size and increase in supply frequency
C) Increase in both conductor size and supply frequency
D) Decrease in both conductor size and supply frequency
57/100
Skin effect is proportional to
A) (Conductor diameter)³
B) (Conductor diameter)½
C) (Conductor diameter)⁴
D) (Conductor diameter)²
58/100
If the sag in an over head line decreases, tension in the line
A) Decreases
B) remains the same
C) Increases
D) will become zero
59/100
Transmission line insulators are made of
A) Glass
B) Iron
C) P.V.C
D) Porcelain
60/100
Which is the first equipment seen in the substation while coming from transmission system?
A) Lightning arrester
B) Circuit breaker
C) Current transformer
D) potential transformer
61/100
Metallic sheath in cables is used to protect the cable from
A) Metallic corrosion
B) corrosion
C) Mechanical injuries
D) chemicals
62/100
Ring system is preferred over radial system because
A) Less cost
B) Reliable & less voltage drop
C) voltage can be reduced
D) poor voltage regulation
63/100
Which of the following is not true regarding HVDC?
A) There is no distance limit for HVDC under ground line
B) HVDC link can operate between two AC systems whose frequencies are equal
C) Corona loss is much more in HVDC transmission
D) the power transmission of bipolar line is same as that of single circuit ac line
64/100
Suburban railways use
A) 600 to 750 V DC
B) 3000 V DC
C) 3.3 KV 3-Φ AC
D) 1100V 1-Φ AC
65/100
Quadrilateral speed-time curve pertains to which of the following service?
A) Main line service
B) Suburban service only
C) Urban service only
D) urban and Suburban service
66/100
The free-running speed of a train does not depend on the
A) Running time
B) Duration of stops
C) Acceleration
D) Distance between stops
67/100
The specific energy consumption for suburban services is usually
A) 18 to 25 watt-hours per tonne km
B) 125 to 150 watt-hours per tonne km
C) 50 to 75 watt-hours per tonne km
D) 155 to 200 watt-hours per tonne km
68/100
Which of the following happens in Kando system?
A) 1-Φ AC is converted into 3-Φ AC
B) 1- Φ AC is converted into DC
C) 3- Φ AC is converted into DC
D) 3- Φ AC is converted into 1- Φ AC
69/100
Longer coasting period for a train results in
A) Higher schedule speed
B) Higher retardation
C) Higher acceleration
D) Lower specific energy consumption
70/100
The friction at the track is proportional to
A) 1/speed
B) speed²
C) speed
D) 1/spee²
71/100
Which one of the following factor affects specific energy consumption of a train?
A) Gradient
B) distance between stops
C) minimum speed
D) maximum speed
72/100
----- wiring system provides best protection against fire.
A) Wooden casing
B) Cleat wiring
C) Metal conduit wiring
D) Capping wiring
73/100
------- wiring is recommended only for temporary installations.
A) . Cleat
B) CTS/RTS
C) Metal
D) PVC capping
74/100
Which of the following is least preferred for earthing?
A) Clayey soil
B) Dry earth
C) Wet mashy earth
D) earth mixed with salt
75/100
What should be the value of earthing resistance for large power stations?
A) 1 ohm
B) 0.5 ohm
C) 2 ohm
D) 5 ohm
76/100
In a break down region, a zener diode behaves like a ------ source.
A) Constant current
B) Constant voltage
C) Constant resistance
D) Constant capacitance
77/100
For a half or full wave rectifier, the peak inverse voltage is always
A) Greater than the input voltage
B) Equal to the input voltage
C) Smaller than the input voltage
D) Greatre than the input voltage for full wave rectifier and smaller for half wave rectifier
78/100
An LED and phototransistor is equivalent to a an
A) opto coupler
B) FET
C) Regulator
D) Thermocouple
79/100
The unwanted characteristics of amplifier output apart from the desired output is collectively termed as
A) Inefficiency
B) Damage
C) Fault
D) Distortion
80/100
If three cascaded amplifiers have gains 10. 20 and 30, the overall gain will be
A) 60
B) 6000
C) 600
D) 6
81/100
The frequency of oscillations of Colpitt's oscillator wo is given by
A) √c₁+c₂/c₁c₂L
B) √c₁c₂/(c₁+c₂) L
C) √c₁+c₂L/c₁c₂
D) √c₁/c₂L
82/100
An LC oscillator cannot be used to produce -------frequencies
A) High
B) Audio
C) Very high
D) very low
83/100
The sum of two octal numbers 75₈ and 256₈ is
A) 331₈
B) 353₈
C) 352₈
D) 341₈
84/100
The AND gate can be constructed with two -------- gates.
A) NAND
B) EX-OR
C) NOR
D) EX-NOR
85/100
As compared to MOS memories, bipolar memories are
A) Slower access time but are cheaper
B) Slower access time and are costly
C) Faster access time and are cheaper
D) Faster access time and are costly
86/100
An 8-bit counter type ADC operates on 1 MHz clock. Its average conversion time is
A) 0.258 ms
B) 1.028 us
C) 0.128 ms
D) 128 ns
87/100
During forward blocking state a thyristor is associated with
A) Large current, low voltage
B) low current, large voltage
C) Large current, large voltage
D) medium current, low voltage
88/100
he VI characteristics of UIT is
A) . Similar to CE with a linear and saturation region
B) Similar to FET with a linear and pinch off region
C) similar to tunnel diode in some respects
D) similar to PN junction diode in some respects
89/100
UJT when used for triggering an SCR. has the waveform
A) . Sine wave
B) Nawtooth wave
C) . Square Wave
D) Trapezoidal
90/100
The object of connecting resistance and capacitance across gate circuit is to protect SCR gate against
A) Noise signals
B) over voltages
C) Over currents
D) dv/dt
91/100
In a 3-Φ full converter the six SCRs are fired at an interval of
A) 120°
B) 30°
C) 60°
D) 45°
92/100
For a full bridge inverter with the following load: R=2Ω X_L=8 Ω and Xc=6 Ω
A) The output voltage lags the current by 45°
B) The output current lags the voltage by 45°
C) The output current lags the voltage by 90°
D) The output current lags the voltage by more than 90°
93/100
The principle of three phase cycloconverter is to
A) add and remove number of SCRS
B) keep the firing angle as 0° for all the devices
C) vary progressively the firing angle of the devices
D) keep the firing angles as 180° for all the devices
94/100
The d.c. motor terminal voltage supplied by a solid-state chopper for speed control purposes varies........with the duty ratio of the chopper
A) inversely
B) parabolical
C) indirectly
D) linearly
95/100
SMPS are based on the principle.
A) Phase control
B) Chopper
C) MOSFET
D) integral control
96/100
-------is used in the rotating type UPS system to supply the mains.
A) Alternator
B) Self excited DC generator
C) DC motor
D) Battery bank
97/100
The 8051 has ------------- parallel I/O Ports.
A) 4
B) 3
C) 5
D) 2
98/100
What does the symbol # represent in the instruction MOV A, #55H?
A) Indexed data type
B) Indirect data type
C) Direct data type
D) immediate data type
99/100
How does the microcontroller communicate with the external peripherals/memory?
A) Via registers only
B) Via I/O Ports
C) Via memory
D) via counter
100/100
Which instruction moves an accumulator to the register from the below mentioned mnemonics?
A) MOV A. Rn
B) . MOV direct. A
C) MOV Rn. A
D) MOV A, @Ri
Result:
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