| Post Name | Electrical Engineer - Kerala State Cooperative Coir marketing Federation Ltd |
|---|---|
| Question Paper Code | 070/2023/OL |
| Category Code | 053/2022, 252/2022, 524/2022 |
| Date of Test | 7 June 2023 |
| Exam Type | Online Examination |
| Total Questions | 100 |
1
Energy stored in a charged capacitor of capacitance C and a potential difference of V is given by
Answer
B. (1/2)CVĀ²
2
If the frequency is more than resonance frequency, then a series RLC circuit will be
Answer
A. Inductive
3
If an impedance is connected across a voltage source V with a source impedance of Z, then for maximum power transfer the load impedance must be equal to
Answer
D. Complex conjugate of Z
4
The reactance oļ¬ered by a capacitance to an AC frquency of 60 Hz is 5 ohm. If the frequency is decreased to 30 Hz, the reactance becomes
Answer
D. 10 ohm
5
The resistance of 9 ohm each are connected in delta. The value of resistance in each phase of equivalent star is _______
Answer
C. 3 ohm
6
The maximum value of mutual inductance of two inductively coupled coils with self-inductance, and is
Answer
D. 48 mH
7
When two coils of equal self-inductance are connected in series in one way the net inductance is 12 mH, and when they are connected in the other way, the net inductance is 4 mH. The maximum value of net inductance when they are connected in parallel in a suitable way is
Answer
B. 3 mH
8
A current of 4 A ļ¬ows in an AC circuit when 100 V DC is applied to it, whereas it takes 250 V AC to produce the same current the power factor of the circuit is
Answer
D. 0.4
9
The voltage across R and L in a series RL circuit is found to be 20 V and 15 V respectively. The RMS value of the voltage across the series combination is
Answer
B. 25 V
10
When an R-L circuit is switched on across a DC source of voltage V volts, the expression for the current is given by
Answer
A. i(t)=(V/R)(1āe^(āRt/L))
11
A magnetic circuit has a m.m.f. of 80 AT and a reluctance of AT/Wb. The magnetic ļ¬ux in the magnetic circuit is
Answer
B. wb
12
Out of the following materials, the area of hysteresis loop will be least for
Answer
C. silicon steel
13
Reciprocal of reluctance is
Answer
C. Permeance
14
According to lenz's law the induced EMF opposes the
Answer
B. Change in Flux
15
The conductor is stationary and magnetic ļ¬eld linked with it is varying. Then the EMF induced in the conductor is known as
Answer
A. Statically induced EMF
16
Which among the following is true about Faraday's law of Electro- magnetic induction?
Answer
D. An EMF is induced in a conductor when the ļ¬ux linked with it is varying
17
A 5 cm long coil has 10 turns and carries a current of 1.5 A. The magnetising force of the coil is
Answer
D. 300 AT/m
18
Relative permeability of free space is
Answer
A. 1
19
Calculate the emf when a coil of 100 turns is subjected to a ļ¬ux rate of 0.3 tesla/sec.
Answer
C. ā30 V
20
A 500 turns solenoid develops an average induced voltage of 60V. Over what time interval must a ļ¬ux change of 0.06 Wb occur to produce such a voltage
Answer
C. 0.5 s
21
The maximum eļ¬ciency occurs in a separately excited generator when the terminal voltage is 220 V and the induced EMF is 240 V. The armature resistance is 2 ohm. The stray losses of the machine is
Answer
B. 200 W
22
The full load copper loss and iron loss of a transformer are 6400 W and 5000 W respectively. The copper loss and iron loss at half load will be, respectively
Answer
A. 1600 W and 5000 W
23
What is the frequency of rotor current of a 50 Hz induction motor operating at 2% slip?
Answer
D. 1 Hz
24
The condition for maximum eļ¬ciency of a DC Machine
Answer
B. Constant loss = Variable loss
25
A 200 V DC shunt motor develops a torque of 54 N-m at an armature current of 10A. The torque produced when armature current is 20 A, is
Answer
A. 108 N-m
26
A 400/200V, 5 KVA transformer has a core loss of 200 W and a full load copper loss of 800 W. The load at which maximum eļ¬ciency occurs is
Answer
D. 2.5 KVA
27
The power factor of a synchronous motor
Answer
C. can be leading, lagging or unity
28
In lap winding, the number of brushes is always
Answer
B. same as the number of poles
29
The purpose of providing dummy coils in a generator is
Answer
D. to provide mechanical balance for the rotor
30
The EMF 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
Answer
D. 580 V
31
The binary code of is
Answer
A. 10101.001
32
Convert BCD 000100100110 to binary
Answer
C. 1111110
33
Binary equivalent of Gray code 0101 is
Answer
D. 0110
34
The logic circuit of binary adder which is used to add 4 bits of binary nos, requires _______ half adder(s) and ________ full adder(s)
Answer
Question Cancelled
35
Given two half adders, What extra two input gate is required to build a full adder?
Answer
C. OR gate
36
How many select lines would be required for an 8 line to 1 line multiplexer
Answer
D. 3
37
The clock frequency of an 8085 microprocessor is 5MHz. If the time required to execute an instruction is 1.4 Ī¼s. Then the no of T states needed for executing the instruction is
Answer
A. 7
38
What is the length of stack pointer
Answer
D. 16 bits
39
PUSH and POP operations are performed by
Answer
B. Stack pointer register
40
Determine the contents of accumulator if the instruction RAL is executed twice. Assume the contents of accumulator is AAH and CY = 0.
Answer
D. A9H
41
A string insulator having 4 units. 33.33% of the total voltage is across the bottom most unit. Its string eļ¬ciency is
Answer
B. 75%
42
Bundled conductors in transmission line will
Answer
C. Improve steady state stability
43
The corona eļ¬ect can be minimized by increasing
Answer
D. Both (2) and (3)
44
The circuit breakers are preferred for substations with
Answer
Question Cancelled
45
For the protection of extra high voltage lines, protective relay used is
Answer
D. Mho type distance relay
46
The power system is subjected to a fault which makes zero sequence component of current to zero. The nature of the fault is
Answer
B. Double line fault
47
With the use of high speed CBs which among the following stability is increased
Answer
C. Transient stability
48
Two identical synchronous machines with equal inertia constants are connected in parallel and oscillating simultaneously. The eļ¬ective inertia constant is 4MJ/MVA. What will be the inertia constant of each machine?
Answer
A. 2 MJ/MVA
49
For transient stability analysis, as long as equal area criterion is satisļ¬ed, the max angle to which rotor angle can oscillate is
Answer
C. Greater than 90Ā°
50
A 4 pole turbo generator is rated at 150 MVA, 14 KV, 60 Hz. Its inertia constant is 12 MJ/MVA. if the input of the generator is suddenly increased to 80 MW for a load of 60 MW. The magnitude of the acceleration of the rotor will be ________ (in ele / )
Answer
C. 120
51
A step up chopper has source voltage 25 V and output voltage 50 V. If the pulse width is 10 Ī¼s, the chopping frequency will be
Answer
A. 50 kHz
52
A single phase fully controlled rectiļ¬er fed DC motor can operate is :
Answer
A. Both forward motoring and reverse
53
An SCR has a half cycle surge current rating of 1500 A for 50 Hz supply. Its one cycle surge current rating will be
Answer
C. 1060.67 A
54
The turn ON time of a SCR with inductive load is 25 Ī¼s. The pulse train frequency is 2 kHz with a duty cycle of 1/10, then the SCR will
Answer
A. turn ON
55
RC triggering is preferred over R triggering circuit because it
Answer
B. provides a larger range of the triggering angle
56
For a single phase half controlled AC voltage converter, the output voltage is 50% of maximum possible output voltage. The ļ¬xing angle is
Answer
Question Cancelled
57
For a Buck converter, in order to reduce the conduction losses in the diode,
Answer
Question Cancelled
58
A three-phase diode bridge rectiļ¬er is feeding a constant DC current of 20 A to a highly inductive load. If three-phase 415 V, 50 Hz AC source is supplying to this bridge rectiļ¬er, then the rms value of the current is each diode in ampere is
Answer
C. 11.55 A
59
A TRIAC is a _________
Answer
C. bi directional current, bidirectional voltage blocking device
60
For UJT to be used as a relaxation oscillator,
Answer
D. It is deliberately designed to operate in the negative resistance region
61
Consider a system with the following transfer function The value of the damping ratio will be 0.5, when the value of k is:
Answer
B. 0.25
62
The impulse response of an Rh circuit is
Answer
Question Cancelled
63
For the unity-feedback system with forward transfer function G(s) = K(Ts + 5)/[sĀ²(1 + Ts)], the feedback system shown in the figure is stable for all positive values of K when:
Answer
C. T > 1
64
The dominant poles of a servo system are located at ā2+j2 and ā2āj2. The damping ratio of the system is
Answer
C. 0.707
65
The initial slope of the Bode magnitude plot of a type 2 system is
Answer
C. ā40 dB/decade
66
A minimum phase system with no zeros has a phase angle of ā270Ā° at its gain cross over frequency. The system is
Answer
B. unstable
67
The root locus plot of the system with open loop transfer function , crosses the imaginary axis at :
Answer
C. does not cross
68
The unit step response of the system G(s) = 10/(s + 15):
Answer
B. no oscillations
69
Zero initial conditions means that the system is:
Answer
B. at rest with no energy stored
70
The damping ratio of a system with a characteristic equation indicates that the system is
Answer
C. undamped
71
A 0 - 250 V voltmeter has an error of Ā±2% of full-scale deļ¬ection. What would be the range of readings if true voltage is 50 V?
Answer
B. 45 V - 55 V
72
In a measurement using an instrument with D'Arsonval movement, the friction in bearings of moving components causes an incorrect reading. This is an example of:
Answer
B. Systematic error
73
It is required that in an electrical substation, voltage of a backup battery bus need to be continuously monitored for 24 hours daily, and the data need to be used for further analysis. Which type of instrument is most suitable for this application?
Answer
C. A recording voltmeter
74
An instrument is used for measuring the Ampere-Hour of a battery charging system. Which class of measuring instruments it belongs to?
Answer
A. Integrating instrument
75
Consider the table given: Construction Connection Measurement Measurement Type Type Type Quantity (P). Moving Iron (R). Series (T). DC only (W). Current (Q). Moving Coil (S). Parallel (U). AC only (X). Voltage (V). DC and AC The all-correct combination that relates all the four columns of the table is:
Answer
A. P-R-V-W, Q-S-T-X, P-S-V-X, Q-R-T-W
76
Power measurement using dynamometer-type wattmeter in low current and high current loads yield diļ¬erent errors when the pressure coil and the current coil are connected diļ¬erently. Consider the table below: Current value Coil Connection Type (P). Low current (R). Pressure coil (T). Load side (Q). High current (S). Current coil (U). Source side The all-correct combination that relates the current value, the coil and the connection type for the least error reading is:
Answer
D. P-S-T, Q-R-T
77
In two-wattmeter method of three-phase power measurement, let the watt meter readings are denoted by P1 and P2 respectively. Read the following 7 statements and choose the correct combination that indicates ALL-TRUE statements. I. P1 = P2 indicates zero power factor II. P1 = P2 indicates unity power factor III. P1 = āP2 indicates zero power factor IV. P2 = 0 indicates 0.5 power factor V. P2 = 0 indicates zero power factor VI. P2 < 0 indicates the power factor is between 0 and 0.5 VII. P2 < 0 indicates the power factor is between 0.5 and 1
Answer
C. II, III, IV, VI
78
In induction-type energy meters, diametrically opposite holes are placed on the rotating aluminium disc. The purpose of this is to:
Answer
B. Prevent creeping of the disc
79
Which of the following is NOT a part of a Digital Energy Meter?
Answer
C. Braking magnet
80
A 1 kHz sinusoidal signal is being observed in a CRO. If the sweep signal is of frequency 500 Hz, the display will show:
Answer
D. Two cycles of sinusoidal signal
81
Fig (a). below shows a discrete signal x[n]. Which is the correct signal that is represented by Fig. (b)?
Answer
B. x[ān+2]
82
The number of lightning strikes in a district is recorded against days of the year. The data is an example of:
Answer
D. Discrete-time random signal
83
Considering the unit impulse function Ī“(t), which of the following statements describes property of Ī“(t)?
Answer
A. Inļ¬nite amplitude at t = 0 and unit area
84
Which of the following functions is a non-periodic one?
Answer
C. x(t)=(cos 2Ļt)u(t)
85
Consider the system described by: , k being a constant. The system is:
Answer
B. Linear and Time-variant
86
Consider the system given by: y[n] = T{x[n]} = 2nx[n]. The system is:
Answer
A. Causal and BIBO unstable
87
Given a signal, . The Nyquist sampling rate for this signal is:
Answer
C. 3 kHz
88
The Zero-Order-Hold transfer function is given by
Answer
C. (1āe^(āsT))/s
89
Consider the following statements: I. Changing the order of the convolution operands does not aļ¬ect the result of the convolution integral. II. Convolution is a linear operation with respect to addition. III. If the two operands of the convolution integral are shifted in time, then the result of the convolution integral is shifted by a duration that is the sum of the individual time shifts introduced in the convolution operands. IV. Convolving a signal with a unit step function produces the running integral of the original signal as a function of time t. Which of the following is correct combination with respect to the statements given above?
Answer
A. All the statements, (I, II, III and IV) are True
90
A ļ¬rst-order hold converts an ideally sampled signal into:
Answer
B. A piece-wise linear signal
91
Which among the following device is used to sense angular position?
Answer
D. Synchro
92
With reference to an LVDT, the secondary windings are connected in diļ¬erential conļ¬guration. The purpose(s) of this is/are to: I. Obtain higher output voltage II. Have phase-sensitive output voltage III. To establish a reference point for the core displacement. IV. Obtain phase-insensitive output voltage Which combinations of the above statements are True?
Answer
C. II and III
93
It is required to measure pressure in a process. For this, a system is proposed that comprises of a Bourdon's tube that senses the pressure and converts into a displacement of its free end. The free and connected to the core of an LVDT, which gives an output voltage corresponding to the displacement. Which of the following is a correct statement for this context?
Answer
B. The Bourdon's tube is a primary transducer and the LVDT is a secondary transducer.
94
Hall-eļ¬ect sensors can be applied to measure:
Answer
D. All the above
95
A few battery cell types are listed below: I. Alkaline cells II. Zinc-carbon cells III. Lead-acid cells IV. Nickel-Cadmium cells V. Lithium-ion cells Which of the below statement is correct with respect to the listing?
Answer
A. I and II are primary cells and III, IV and V are secondary cells
96
A battery is rated for 100 Ah, 1C. If this battery is discharged at 0.5 C, how long it can supply energy, and at what current?
Answer
C. 2 hours, 50 A
97
Which of the following IE rule concerns about the connection to earth?
Answer
D. IE 67
98
Consider the table below: Device Protect against P. MCB R. Overload Q. RCCB S. Short-circuit T. Earth-leakage U. Electric shock Which of the following combinations is all-correct with respect to the given table?
Answer
B. (P, R, S), (Q, T, U)
99
Which among the following is Not used as an earthing-enhancement compound?
Answer
D. Dolomite
100
Two lamp posts of height 3 m are separated by 8 m on ground. Each lamp post is having a lamp with 500 CP intensity. What is the illumination (in lux) at the middle point on ground between the two posts?
Answer
Question Cancelled
Discussion
Ask a doubt or share a tip.
No comments yet ā start the discussion.