AP ECET 2012 (EEE) Question Paper with Answers

1/100
In a given below circuit, at resonance Iʀ is equal to
(a) 0A
(b) 10A
(c) 5A
(d) 0.5A
2/100
As altrnating current a peak value of 2A .If is Peak Factor is √2 and from factor is π/2√2 , them it's average value is
(a) 8/πA
(b) 4/πA
(c) π/2A
(d) π/4A
3/100
The pover factor of an incandescent bulb is
(a) 0.8 lagging
(b) 0.8 leading
(c) unity
(d) zero
4/100
4. The power factor of a circuit comprising resistance R and reactance X in series is
(a) R√R² +X²
(b) X√R²+X²
(c) R/R²+X²
(d) X/R²+X²
5/100
The working principle of a Transformer in
(a) Electromagnetism
(b)Conduction
(c)Energy transfer
(d)Mutual induction
6/100
The equivalent resistance of transformer having tranfarmation ratio (K) = 5 and R₁=0.1Ω when referred to secondary is
(a) 150Ω
(b) 0.02Ω
(c) 0.004Ω
(d) 2.5Ω
7/100
Whit is load at which maximum efficiency occurs in ease of a 100 KVA transformer with iron loss of 1 kW and full load copper loss of 2 kW -
(a) 100 KVA
(b) 70.7kVA
(c) 50.5kVA
(d) 25.2 KVA
None of the above
8/100
In high frequency transformers, the material used for core is
(a) Ferrite
(b) Iron
(c) Cast iron
(d) Silica
9/100
Buchholz relay is used to
(a) identify faults
(b) rectify the fault
(c) trip-off connections when fault exists
(d) clears the fault
10/100
Distribution transformers are designed to keep core losses minimum and copper losses are relatively less important because
(a) The primary of such transformers are energized for all the 24 hours in a day core loss occur throughout the day while copper loss occur only when the secondary is supplying the load
(b) To ensure maximum All-day efficiency
(c) Greater core losses my destroy in insulation
(d) Greater core losses will heat up the oil of the transformer rapidly
11/100
Which one of the following methods gives more accurate result for determination of voltage regulation of an alternator
(a) MMF method
(b) Synchronous impedance method
(c) Potier triangle method
(d) ASA method
12/100
12. Hydrogen is used in large alternators mainly to
(a) reduce distortion of waveform
(b) cool the machine
(c) strengthen the magnetic field
(d) reduce eddy current losses
13/100
The frequency of emf generated in an 8-pole alternator running at 900 rpm is
(a) 50 Hz
(b) 120 Hz
(c) 90 Hz
(d) 60z
14/100
14. The angle between synchronously rotating stator flux and rotor poles of a synchronous motor is called ----- Angle
(a) Synchronizing
(b) slip
(c) Power factor
(d) Torque
15/100
If, θₑ be the electrical angle and θₘ be the mechanical angle and P be the number of poles of synchronous motor, then which one of the following relation is true?
(a) θₑ = p×θₘ
(b) θₑ = (P/2) ×θₘ
(c) θₑ =θₘ /P
(d) θₑ =P/θₘ
16/100
The essential condition for parallel operation of two single phase transformers is that they should have same
(a)Polarity
(b) KVA rating
(c) Voltage ratio
(d) Percentage impedance
17/100
The V-curve of synchronous moter is a plot of
(a) State current versus stator power factor
(b) Stator current versus rotor current at all loads
(c) Stator current versus rotor currents when power delivered is constant
(d) Stator current versus power delivered
18/100
A wound rotor induction motor runs with a slip of 0.03 when developing full load torque. Its rotor resistance is 0.25 ohm per phase. If an external resistance 0.50 ohm per phase is connected across the slip rings, what is the ship for full load torque?
(a) 0.03
(b) 0.06
(c) 0.09
(d) 0.1
19/100
19. The torque developed in a three phase induction motor depends on
(a) stator flux and rotor current
(b) stator flux and stator current
(c) stator current and rotor flux
(d) rotor current and rotor flux
20/100
. A single phase ac induction motor is not self starting because it has
(a) No slip
(b) rotor is short circuited
(c) high intertia
(d) absence of rotating magnetic field
21/100
1.A single phase winding in a single phase motor produces
(a) an alternating magnetic field
(b) a stationary magnetic field
(c) a rotating magnetic field
(d) a steady magnetic field
22/100
Under no-load conditions, power factor an induction is about
(a) 1.2 lag
(b) 0.9 lag
(c) Unity
(d) 0.5 lead
23/100
Of all the plants, minimum quantity of fuel used is required in ---plant
(a) Diesel power
(b) Steam
(c) Hydro-electric
(d) Nuclear
24/100
The overall efficiency of a Thermal Power Station is
(a) η boiler
(b)η boiler × η generator
(c) η generator × η boiler
(d) η tarbin × η boiler
25/100
The effect of water hammer can be minimized by using
(a) Spill way
(b) Anvil
(c) Surge Tank
(d) Draft tube
None of the above
26/100
In a diesel power plant suspended impurities in the fuel are removed by
(a) Cyclone separators
(b) Electrostatic separators.
(c) Fabric filtera
(d) Strainer
27/100
The rupturing capacity of a circuit breaker is measured in
(a) Ampere
(b) Volt-Ampere
(c) Watt
(d) Valt
28/100
A circuit breaker is essentially
(a) An are extinguisher
(b) A current interrupting device
(c) power factor correcting device
(d) A device for neutralizing the effect of transients
29/100
Mho relay normally is used for protection of
(a) Long transmission lines
(b) Medium Transmission lines
(c) Short transmission lines
(d) No length criterion
30/100
The scheme adopted for bus-bar protection is
(a) spilt-phase protection
(b) differential protection
(c) over current protection
(d) reverse power protection
31/100
Due to the ferrari effect on long overhead lines---------
(a) receiving end voltage is less than sending voltage
(b) receiving end voltage is more than sending voltage
(c) receiving end voltage is equal to sending voltage
(d) receiving end voltage is not effected
32/100
Corons occurs between two transmission lines when they are
(a) closely spaced
(b) widely spaced
(c) having high potential difference
(d) carrying DC power
33/100
Surge impedance of a transmission line is given by
(a) √(L / C)
(b) √ (C/L)
(c) √LC
(d) 1√LC
34/100
The general distance for short transmission line is
(a) less than 80 km
(b) 80 km-250 km
(c) more than 250 km
(d) 150 km-100 km
35/100
35 The resistance of the line
(a) increases with increase in frequency
(b) decreases with inrease in equency
(c) is independent of frequency
(d) increases with decrease in frequency
36/100
In HVDC Transmission System AC is converted to DC using
(a) Rectifier
(b) Inverter
(c) Chopper
(d) Cycloconverter
37/100
Suspension type insulators are used for voltages beyond
(a) 220 V
(b) 400V
(c) 11KV
(d) 33 KV
38/100
Power Factor of Industrial loads is geurally
(a) Unity
(b) Leading
(c)Lagging
(d) Zero
39/100
Pole mounted transformer stations are meant for
(a) Primary transmission
(b) Primary distribution:
(c) Secondary transmission
(d) Secondary distribution
40/100
Transmission lines are transposed to
(a) Reduce copper loss
(b) Reduce skin effect
(c) Prevent interference with communication lines
(d) Present short circuit between conductors
41/100
The units for specific energy consumption related to traction is
(a) Watt-Hour/ Tonne-km
(b) watt-Hour/km
(c) Joules/Sec
(d) Watt
42/100
In Kando system of track electrification---- is converted into-----
(a) sinngle phase, dc
(b) dc, single phase
(c) single phase, three phase
(d) three phase, single phase
43/100
A train has a scheduled speed of 60 kmph between the stops which are 6 km apart. The actual rum time is ------ if the duration of stop is 60 sec
(a) 60 sec
(b) 360 sec
(c) 240 sec
(d) 300 sec
44/100
Average speed of a train is dependent on
(a) Distance between two stops & run time
(b) Run time & stop time
(c) Stop time & acceleration
(d) Acceleration & deceleration
45/100
The electric motos used for traction work should have ------
(a) Low starting torque
(b) High starting torque
(c) Rise in speed with increase in load
(d) No braking capability
46/100
Tractive effort of an electric locomotive can be increased by
(a) Increasing the supply voltage
(b) Increasing the speed
(c) increasing the dead weight over the driving axles
(d) Using high rating motors
47/100
Tractive effort required for a train going down from an upgradiant is
(a) less than tractive effort on level track
(b) more than tractive effort on level track
(c) equal to the tractive effort on level track
(d), independent of mass of the train
48/100
The area under speed-time curve of a train represents
(a) average speed
(b) average acceleration
(c) distance travelled
(d) average velocity
49/100
As the number of wire gauge increases the cross sectional areas of wire.
(a) increases
(b) remains same
(C) becomes neglible
(d) decreases
50/100
Which of the following wiring is not visible outside?
(a) conduit wiring
(b) cleat wiring
(c) casing and capping wiring
(d) concealed wiring
51/100
Resistance of earth system of power station should not exceed the limit of
(a) 0.5 ohms
(b) 2 ohms
(c) 1 ohms
(d) 5 ohms
52/100
In electrical installations the fuse is always connected in ----- wire
(a) earth
(b) neutral
(c) phase
(d) ground
53/100
The transistor used in amplifier circuits operates in
(a) Active region
(b) Saturation region
(c) Cut off region
(d) Reverse region
54/100
The gain of an amplifier is given by the following formula
(a) G(dB) =10 log(Pm /P out )
(b) G(dB) =10 log(pout)
(c) G(dB) =10| log (P out/P in)
(d) G(dB) =10 log(P in )
55/100
The number of diodes that are used in half wave rectifier and full wave bridge rectifier are
(a) 1.2
(b) 1,4
(c) 2.4
(d) 2.1
56/100
The average voltage of a fall wave rectifier fed from are ac source of peak voltage,Vm and frequency 50 Hz is
(a) V m/π
(b) 2V m / π
(c) V m / √2
(d) V m/2
57/100
In a transistor which of the following layer is lightly doped
(a) Emitter
(b) Collector
(c) Drain
(d) base
58/100
Zener diode regulates
(a) Voltage
(b) Resistance
(c) Current
(d) power
59/100
The frequency of oscillation of wein bridge oscillator in Hz is
(a) 1/2 π RC
(b) 2 π RC
(c) 1/RC
(d) R/C
60/100
XYZ+(XYZ overline ) XYZ + XY bar Z
(a) XYZ
(b) X
(c) Z
(d) 0
61/100
The 2's complement of the number D 1001 1100 is
(a) 0110 0011
(b) 0110 0100
(c) 1001 1100)
(d) 1001 1101
62/100
The boolean expression for NOR gate with inputs A and B is
(a) A+B
(b) A.B
(c) A + B
(d) overline A + B
63/100
A DAC with 8 input bits has --- resolution compared with DAC with 4 input bits
(a) High
(b) Same
(c) Low
(d) Infinite
64/100
The power electronic device, Silicon Controlled Rectifier has
(a) Two junctions and three layers
(b) Three junctions and three layers
(c) Three junctions and four layers
(d) Two junctions and two layers
65/100
Which one of the following is a bidirectional Controlled switch
(a) Thyristor
(b) Triac
(c) GTO
(d) Diac
66/100
If the gate current of an SCR is increased, its forward break over voltage V_bo will
(a) Increase
(b) Decrease
(c) Not be affected
(d) Beinfinity
67/100
In an UJT triggering circuit for SCR, pulses are generated at of UJT
(a) Emitter
(b) Base 1 (B1)
(c) Base 2 (B2)
(d) B1-B2
68/100
In a half wave controlled rectifier feeding R-L load, the range of firing angle of thyristor is
(a) 0<=α <= 180°
(b) 90 <=α <=180°
(c) 0 <= α <= 90°
(d) 0 <= α <= 360°
69/100
The DC output voltage. Vₒ of a basic chopper circuit with input voltage, V_iɴ and duty cycle, δ is given by
(a) Vₒ = V _iɴ × δ
(b) Vₒ =V _iɴ / δ
(c) Vₒ=V_iɴ /(1-δ )
(d) Vₒ = V _iɴ
70/100
An AC regulator provides
(a) Variable frequency, fixed magnitude AC
(b) Fixed frequency, Variable magnitude AC
(c) Fixed frequency, fixed magnitude AC
(d) Variable frequeres, variable magnitude AC
71/100
The output voltage el a single phase bridge inverter is
(a) Square wave
(b) sinusoidal wave
(c) Constant dc
(d) Trianular wave
72/100
Two quadrant operation of dc motor can be obtained if it is fed from a
(a) Uncontrolled convertor
(b) Half controlled convertor
(c) Half wave convertor
(d) Fully controffcd convertor
73/100
For controlling the speed of a 3 phase induction motor V/f ratio is maintained constant fo
(a) Constant air gap flux
(b) Constant reactance
(c) Varying the air gap flax
(d) Variable resistance
74/100
8051 microcontroller has --- data lines and ------ address lines
(a) 16.8
(b) 8.8
(c) 8, 16
(d) 16.20
75/100
Which of the following instruction is not a data transfer instruction?
(a) XCH
(b) PUSH
(c) ADD
(d) MOV
76/100
Internal memory of 8051 micro controller consists of
(a) 128 bytes of RAM. 2K bytes of ROM
(b) 4K bytes of RAM, 128 bytes of ROM
(c) 2 K bytes of RAM 128 bytes of ROM
(d) 128 bytes of RAM, 4 K bytes of ROM
77/100
The highest priority interrupt is
(a) TF1
(b) IE 1
(c) TP0
(d) IEO
78/100
Percentage Voltage regulation of a transmission line is given by
(a) (Eₛ —Eᵣ)Eᵣ *100
(b)(Eᵣ — Eₛ) / Eᵣ* 10|
(c) (Eₛ — Eᵣ ) / Eₛ *100
(d) (Eᵣ— Eₛ ) / Eₛ * 100
79/100
In a main line service of electric traction system
(a) Distance between two stops is very small
(b) Acceleration and retardation periods are small
(c) Free running and coasting periods are short
(d) Acceleration and retardation periods are long
80/100
For SCR, dv/dt protection is achieved by connecting --------
(a) L in series with SCR
(b) RL in series with SCR
(c) RC in series with SCR
(d) RC in parallel with SCR
81/100
The effective resistance between terminals A and B in the below figure is
(a) r
(b) 2r
(c) 3r
(d) 4r
82/100
If I be the current, C be the capacitance and V be the potential differences, the I/CV will have the unit of
(a) Time
(b) Power
(c) Frequency
(d) Reactive Power
83/100
In a series R-C circuit excited the DC voltage E., the initial current is
(a) E/R
(b) 0
(c) E/C
(d) C/E
84/100
The strength of electromagnet can be increased by
(a) Decreasing the length of the conductor
(b) Increasing the length of the conductor
(c) Increasing the number of turns
(d) Decreasing the number of turns
85/100
Tesla is a unit of
(a) Flux
(b) Field strength
(c) Current
(d) Flux density
86/100
According to joule's law heat produced by an electric current is proportional to
(a) square of the resistance
(b) potential difference
(c) square of the current.
(d) square of the time
87/100
The Thevenin's equivalent resistance R_th for given below network is BThe Thevenin's equivalent resistance R_th for given below network is
(a)1Ω
(b) 2Ω
(c) 4Ω
(d) Infinity
88/100
In a differential compound generator, the series field turns are provided on
(a) Armature
(b) Commutator
(c) interpole
(d) Main pole
89/100
The function of the commutator in a dc machine is
(a) to change alternating current to direct current
(b) to improve commutation
(c) for easy good control
(d) to change alternating voltage to direct voltage
90/100
If N is the speed and P is number of poles, then the frequency of induced e.m.f in DC generator will be
(a) NP/60
(b) NP/120
(c) NP/2
(d) NP
91/100
The demagnetizing flux in dc generator
(a) Increases e.m.f
(b) Decreases e. m.f
(c) Increases speed
(d) Decreases speed
92/100
If Tₐ be the torque and Iₐthe armature current for a dc series motor, then which of the following relation is valid before saturation
(a) Tₐα lₐ
(b) Tₐ α (I/I ₐ)
(c) Tₐ α (Iₐ²)
(d) Tₐ α ( I /Iₐ)²)
93/100
What will happen if the back e.m.f of a DC motor vanishes suddenly
(a) The motor will stop
(b) The motor will continue to run
(c) The armature may burn
(d) The motor will run noisy
94/100
The mechanical power developed by a DC motor is equal to
(a) Power input + losses
(b) Back e.m. × farmature current
(c) Power output × losses
(d) Power output × efficiency
95/100
Neglecting saturation if current taken by a series motor is increased from 10A to 12A, the percentage increase in its toque is
(a) 20%
(b) 44%
(c) 30.5%
(d) 16.6%
96/100
Dynamometer type instrument have
(a) Cramped scale at the beginning
(b) Cramped at the end
(c) Cramped at the middle
(d) Uniform scale
97/100
To measure a signal of 10 mV at 75 Hz, which one of the following instrument can be used
(a) cathode ray oscilloscope
(b) VIVM
(c) Moving Iron voltmeter
(d) digital multimeter
98/100
Which one of the following a passive transducer
(a) piezolectric
(b) thermocouple
(c) photovoltaic cell
(d) LVDT
99/100
The voltage coil of a single phase house energy meter
(a) is highly resistive
(b) is highly inductive
(c) is highly capacitiv
(d) has a phase angle equal to power factor ange
100/100
100. The effective value of a triangular wave is
(a) Max. Value
(b) √3( Max. Value
(c) √3/Max.value
(d) Max. Value/√3
Result:
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