| Post Name | DEPUTY ENGG.(Electrical), ASST. ENGG. (Electrical) - K CO-OP M MARKETING FEDN. Ltd.., KSEB |
|---|---|
| Question Paper Code | 098/2023 |
| Category Code | 220/2021, 221/2021, 439/2022 |
| Date of Test | 30 June 2023 |
| Medium of Question | ENGLISH |
| Exam Type | OMR Examination |
| Total Questions | 100 |
1
How much time does a capacitor take to build up a charge with 10 mJ of energy, if
the charging current of 100 mA taken by a 100 µF capacitor ?
Answer
C. 14.14 ms
2
A resistance load being connected to a dC network, receives maximum power when
the load resistance is equal to the internal resistance of the source network as seen
from the load terminals.
Answer
A. maximum power transfer theorem
3
An lC circuit stores a total energy of E and the maximum charge on the capacitor
is assumed as Q. What will be the energy stored in the inductor while the charge on
the capacitor is Q/2 ?
Answer
D. 3E/4
4
What will be the equivalent inductance seen between the terminal
Answer
B. 1 H
5
Average current value of a Sine wave is
Answer
B. 0.636 IPeak
6
For mutually coupled coils L₁ and L₂, the mutual inductance is given by
Answer
D. None of the above
7
The equation for EMF induced in a coil rotated in uniform magnetic field by an angle θ
from its vertical position
Answer
D. EmSinωt
8
The bandwidth of an RlC series circuit with resistance, inductance and capacitance
of 10 Ω, 0.1 H and 8 µF respectively is
Answer
A. 15 Hz
9
A series RLC circuit has oscillatory transient current when:
Answer
A. R < 2√(L/C)
10
State the graph shown here correspond to which category
Answer
B. Variation on impedance and current in a parallel resonant circuit
11
As the temperature increases beyond the curie temperature, the relative susceptibility
of ferromagnetic materials
Answer
D. decrease
12
If the area of hysteresis loop of a material is large, the hysteresis losses in the material
will be
Answer
B. large
13
The total inductance of 2 coils connected in series cumulatively is 1.6 H and connected
in differentially is 0.4 H. If the self inductance of one coil is 0.6 H then coupling
coefficient will be
Answer
A. 0.612
14
The induced emf in a magnetically linked coil when its flux is changed from 1 Wb to
0.1 Wb in 0.1 second is
Answer
D. 9 V
15
The potential at a point due to a charge of 100 µCoulomb at a distance of 9 metres is
Answer
B. 105 Volts
16
A circular wire loop has its radius increasing at a rate of 6m/s. The loop is placed
perpendicular to a constant magnetic field of 0.4 Wb/m2. When radius of the loop is
2m, the emf induced in the loop will be
Answer
D. 9.6 π Volts
17
What will be the force experienced by the conductor when a current of 50 A flows
through the conductor of length 0.5 m placed in a magnetic field of strength 0.5 wb/m2 ?
Answer
A. 12.5 N
18
A circuit carrying a triangular wave having a form factor
Answer
A. Greater than 1.11
19
The RMS value of the shown half-rectified square wave, v = 10 V for 0 ≤ t < T/2 and v = 0 for T/2 ≤ t < T, is:
Answer
B. 7.071 V
20
The primary objective for making the coil span of a dC armature winding equal to a
pole pitch is to
Answer
Question Cancelled
21
The primary objective of commutating or reversing emf in dC machine is to
Answer
Question Cancelled
22
Under light load condition a series generator has rising voltage characteristics, but
at a high loads the voltage starts decreasing due to
Answer
D. Excessive demagnetising effects of armature reaction
23
A 250 V shunt motor with armature resistance of 0.5 Ω runs at 600 rpm on full load
and takes an armature current of 20 A. If resistance of 1.0 Ω is placed in the armature
circuit, then the speed at half-full load torque is
Answer
A. 587.5 rpm
24
In a retaration test on a separately excited motor, the induced emf in the armature fall
from 220 V to 190 V in 30 seconds on removing the armature from the supply. The
same fall take place in 20 seconds if immediately after disconnection the armature
is connected to a resistance which takes 10 A during this fall. Then the stray losses
of the motor is
Answer
D. 4100 W
25
If the applied voltage of a certain transformer is increased by 50% and the frequency
is reduced to 50% the maximum core flux density at secondary side will be
Answer
D. 3Bm1
26
A 3 phase 16 pole alternator has 144 slots, then the distribution factor in the machine is
Answer
A. 0.959
27
The eddy current loss of a transformer at 150 V, 60 Hz is 175 W. What will be the
eddy current loss is frequency has reduced to 30 Hz at 150 V ?
Answer
C. 175 W
28
A 3-φ, 50 Hz, induction motor has a full load speed of 1440 rpm. If the machine is
running at this condition, what will be the rotor slip and rotor frequency of the induction
motor ?
Answer
B. 4%, 2 Hz
29
An alternator has 18 slots/pole and the first coil lies in slots 1 and 16, then the pitch
factor for 3rd harmonics is
Answer
D. 0.707
30
What type of motor can be permanently coupled with heavy loads ?
Answer
C. Series motor
31
(39)10 in binary systems is
Answer
D. 100111
32
Which of the following circuits can be used as parallel to serial converter ?
Answer
A. multiplexer
33
Simplifying (X + Y) (X + Y) we will get
–
Answer
D. X
34
How many outputs are there in the output of a 10 bit d/A converter ?
Answer
C. 1024
35
What is the least change in output voltage of 12 bit binary d/A converter using 12 V
reference supply voltage ?
Answer
B. 0.00293
36
A 4 bit synchronous counter uses flip-flops with propagation delay time of 15 ns each.
The maximum possible time required for change of state will be
Answer
A. 15 ns
37
How many kilobytes of memory will be able to access a microprocessor with 12 bit
address bus ?
Answer
C. 4
38
A ring counter is same as
Answer
A. Shift counter
39
A gate in which all inputs must be high to get a low input is called
Answer
Question Cancelled
40
In 8085, TRAP is
Answer
C. used for catastrophic events like temporary power failure
41
The __________ components consists of three vectors equal in magnitude and
phase.
Answer
C. Zero sequence
42
Inductance per phase of a three-phase transmission line is:
Answer
Question Cancelled
43
If the voltage across each disc insulator in a string is equal then calculate the string
efficiency.
Answer
B. 1
44
Which faults are very severe faults ?
Answer
B. Three phase fault
45
What are the various type of shunt faults ?
Answer
A. line to ground fault
46
Generator emf is 1 p.u. and transient reactance is 25%. Find the transient current.
Answer
Question Cancelled
47
Give an expression for the swing equation.
Answer
B. M d²δ/dt² = P_m − P_e
48
If maximum power P_max = 50 MW, find the electrical power output for a torque angle of 60°.
Answer
A. 43.3 mW
49
In which bus real and reactive components of power are specified ?
Answer
B. load bus
50
In ___________ method the convergence is not affected by the choice of slack
bus.
Answer
C. Newton Raphson
51
Closed loop transfer function of the following system is
R(s)
G4
+
R(s) + G1 + G2 G3 + G5 C(s)
– – –
H1 H2
G1.G2.G3.G4 + G1.G2.G3.G5
Answer
C. 1 + G2.H1 + G5.H2 + G2.G5.H1.H2 + G1.G2.G4.G5 + G1.G2.G3.G5
52
The open loop transfer function with unity feedback is given by G(s) = , the
S(S + 2)
poles of the closed loop system are located at
Answer
C. (–1, –1)
53
Unit step response of 2nd order system is 1 – e–5t – 5te–5t. Which of the following
statements are correct ?
i. Impulse response is 10e–5t.
ii. damping ratio is 1.
iii. Undamped natural frequency is 5rad/sec.
Answer
B. ii and iii only
54
Closed loop transfer function of the following system is
R(s)
G1 G2 G3 G4
R(s) C(s)
–1
–1 –1
–1
G1.G2.G3.G4
Answer
A. 2 + 2.G4 + 2.G3.G4 + G2.G3.G4
G1.G2.G3.G4
55
Phase margin is the amount of angle to make the system
Answer
Question Cancelled
56
The open loop transfer function of a unity feedback system is given by
3e−2s
G(s) = . The gain crossover frequency in rad/sec is
s(s + 2)
Answer
C. 1.26
57
Range of k for stability of the unity-feedback system with open-loop transfer function G(s) = k/[s(s+1)(s+2)(s+5)] is:
Answer
D. 0 < k < 19.69
58
Consider the following systems
1
System 1 :
2s + 1
1
System 2 :
5s + 1
Which of the following statement is true ?
Answer
A. Bandwidth of System 1 is greater than System 2
59
Condition for stability of a closed-loop system with characteristic equation s³ + bs² + cs + 1 = 0 is:
Answer
D. bc >1
60
Consider the following systems
10
System 1 :
s +1
10
System 2 :
s+2
Which of the following statement is true ?
Answer
B. System 1 is slower than System 2
61
An SCR is rates 450 V, 75 A. How many SCRs are required to be cascaded to form
a circuit of 9 kV, 75 A rating ? let the derating factor is 20%
Answer
C. 25
62
An half controlled single phase bridge rectifier in continuous load current mode is
supplying an RL load operating at firing angle α. Fraction of cycle for which the free
wheeling diode conduct is
Answer
D. α/π
63
A step-up chopper has an input voltage of 100 V and an output voltage of 250 V.
The ON time of the chopper is 75 µs. Time period of the chopper in µs is
Answer
A. 125
64
A three phase full bridge voltage source inverter delivers power to a star connected
resistive load of 10 Ω/phase from a 450 V dC source. RmS value of load current per
phase under 180° conduction mode will be
Answer
B. 21.20 A
65
In a thyristor
Answer
B. Holding current is less than latching current
66
An Op-Amp has an output signal of 2 V for an input of 50 mV. The voltage gain in dB is
Answer
B. 32 dB
67
In response to a square wave input, the output of an Op-Amp changed from
–3 V to + 3 V over a time interval of 0.25 µs. The slew rate in V/µs of the Op-Amp will be
Answer
D. 24
68
In single pulse modulation of PWm inverter, 3rd harmonics can be eliminated if the
pulse width is
Answer
D. 120°
69
A step-down chopper operates in continuous-conduction steady state with duty ratio D. The relation V_o/V_in is:
Answer
A. D
70
The magnitude of output voltage Vo of the below circuit is
2k
3k
–
2V
Vo
+
1k
Answer
A. 1.33 V
71
The resistance of a circuit is found by measuring the current flowing through and power
fed into the circuit. If the limiting error in the measurement of power and current are
± 1.5% and ± 2.5% respectively, the limiting error in the measurement of resistance
will be
Answer
A. ± 6.5%
72
A voltmeter with a full-scale range of 0 – 50 V and has a sensitivity of 1kΩ /volt is used
to measure the potential across a resistive network as shown in the figure below, the %
relative error in the measurement will be
100 kΩ
+ 50 kΩ
150 V Voltmeter
–
Answer
D. 40.00
73
A basic d Arsonval movement has full scale current of 1mA and internal resistance
of 100 Ω is used to convert a multirange dC voltmeter with the ranges of 0 – 20 V,
0 – 50 V, 0 – 100 V and 0 – 250 V as shown below. The value of R1 and R2 respectively
R4 R3 R2 R1
100 V 50 V
meter
250 V 20 V
+
–
Answer
B. 19.9 kΩ and 30 kΩ
74
Three phase power measurement using two-wattmeter method, the reading of the
two wattmeters will be equal and opposite when
i. Phase angle is 90° lagging.
ii. Phase angle is 0°.
iii. Phase angle is 90° leading of these statement.
Answer
D. i and iii are correct
75
Consider the statements below :
i. The compensating coil of a low power factor wattmeter compensates the effect
of the power consumed by the pressure coil.
ii. The compensating coil of a low power factor wattmeter compensates the effect
of power consumed by the current coil.
iii. The compensating coil of a low power factor wattmeter compensates the effect
of the friction of moving coil.
Answer
C. i is true but ii and iii are false
76
A symmetrical sawtooth wave form has an amplitude of ±100 V is applied to full wave
rectifier type AC voltmeter. The meter reading will be
Answer
B. 57.73 V
77
If a 0 – 2A moving iron ammeter has an internal resistance of 100 mΩ and inductance
of 0.1 mH. A shunt coil is used to extend its range to 0 – 20 A for all operating
frequencies. The time constant in milliseconds and resistance in mΩ of the shunt
coil respectively are
Answer
B. 1, 11.11
78
The current through the moving iron instrument has increased by 30%, what is the
percentage increase in the deflection torque ?
Answer
C. 69
79
A single-phase energy meter is measuring the energy consumption of a unity power
factor constant load for 2 hours. If the meter disc makes 2300 revolutions for a 230 V,
20 A load current, what will be the meter constant ?
Answer
B. 250
80
Two in phase 50 Hz sinusoidal wave forms of Peak-to-peak value 2 V is fed into
the channel-1 and channel-2 respectively of an oscilloscope. If the voltage scale, time
scale and other settings are exactly the same for both the channels. What would be
observed Lissajous pattern if the oscilloscope is operated in X-Y mode ?
Answer
D. A straight line inclined at 45° with respect to the x axis
81
A continuous-time signal is x(t) = 3t/4 for 0 ≤ t ≤ 4 and zero otherwise. Which graph represents x(t/2)?
Answer
B. Ramp 0≤t≤8 ending at 3
82
Odd component of given discrete time signal X[n] is
X{n]
4
3
1
1012345
4
4-3-2-11f1
Answer
C. 1 n
83
If P and E are average power and energy of a continuous- or discrete-time signal, an energy signal has
Answer
A. 0 < E < ∞, P = 0
84
For a continuous time system described by y(t) = x(t/2) is
Answer
D. linear and stable
85
Let x(t) = cos(t). Then x(t)δ(t − π) is:
Answer
D. −δ(t − π)
86
The fundamental period of the discrete signal x[n] = e^(jπn/2) is:
Answer
B. 4 s
87
The response of lTI continuous time system to the unit step input is given by
1
(1 – e–3t ), then the impulse response of the system is
3
1
Answer
B. e–3t
88
The impulse response h(t) of a LTI continuous time system is described by
h(t) = eαtu(t) + eβtu(–t) where u(t) denotes the unit step function, α and β are real
constants. This system is stable if
Answer
D. α is negative and β is positive
89
Consider the signal x(t) = sin (3πt) + sin (6πt), the minimum sampling interval to satisfy
the Shannon’s sampling rule is
Answer
A. 1/6 s
90
Let x(t) = 2u(t) and y(t) = u(t). Then x(t) * y(t) is:
Answer
C. 2t
91
The table below show the combinations of signal conditioning circuits of the different
types of transducers, out of these, the correct combinations are
Transducer Signal conditioning circuit
P. Piezoelectric Charge amplifier
Q. Strain gauge Phase sensitive detector
R. Thermocouple Cold junction compensation
S. l.V.d.T. AC Bridge
Answer
C. P and R
92
A resistance wire strain gauge with a gauge factor of 2 is bonded to a steel structural
member subjected to a stress of 150 mN/m2. The modulus of elasticity of steel is
200 GN/m2. The change in the value of gauge resistance due to the applied stress
will be
Answer
A. 0.15%
93
A suitable value of a fixed resistance is usually connected across a thermistor is to
Answer
B. Improve the linearity
94
Hall sensor is used to measure
Answer
D. All the above
95
The electrolyte of nickel-cadmium rechargeable cells is a mixture of
Answer
D. Potassium hydroxide and deionized water
96
Which of the following arrangement will get the maximum current in a 3 Ω resistor
in the case of 24 cells, each has internal resistance of 2 Ω ?
Answer
C. 6 cells in series with 4 rows in parallel
97
According to the Bureau of Indian Standards, the minimum vertical clearance of low
and medium voltage lines from the building shall be
Answer
D. 2.5 m
98
The minimum size of copper plate electrode used for earthing should be
Answer
C. 600 mm × 600 mm × 3.15 mm
99
A lamp emitting light uniformly in all directions has a mean spherical candle power
of 25. What will be the total luminous flux radiated by the lamp in all directions ?
Answer
A. 314 lumens
100
Correct combinations given in the table is
Column I Column II
P. luminous Flux lumen
Q. luminous intensity Candle power × Solid angle
R. lumen Candela
S. lux lumen/m2
Answer
D. P and S
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