Website : www. aceengineeringpublications.com Electrical Engineering (Volume - I) (Engineering Mathematics, Electrical Materials, Electric Circuits & Fields, Electrical and Electronic Measurements, Computer Fundamentals, Basic Electronics Engineering) Previous years Objective Questions with Solutions, Subjectwise & Chapterwise (1992 - 2018) ACE Engineering Publications (A Sister Concern of ACE Engineering Academy, Hyderabad) Hyderabad | Delhi | Bhopal | Pune | Bhubaneswar | Bengaluru | Lucknow | Patna | Chennai | Vijayawada | Visakhapatnam | Tirupati | Kukatpally | Kolkata ACE is the leading institute for coaching in ESE, GATE & PSUs H O: Sree Sindhi Guru Sangat Sabha Association, # 4-1-1236/1/A, King Koti, Abids, Hyderabad-500001. Ph: 040-23234418 / 19 / 20 / 21, 040 - 24750437 7 All India 1 st Ranks in ESE 43 All India 1 st Ranks in GATE ESE - 19 (PėĊđĎĒĘ)
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Website : www. aceengineeringpublications.com
Electrical Engineering(Volume - I)
(Engineering Mathematics, Electrical Materials, Electric Circuits & Fields, Electrical and Electronic Measurements, Computer Fundamentals, Basic Electronics Engineering)
Previous years Objective Questions with Solutions, Subjectwise & Chapterwise (1992 - 2018)
ACEEngineering Publications
(A Sister Concern of ACE Engineering Academy, Hyderabad)
ACE is the leading institute for coaching in ESE, GATE & PSUsH O: Sree Sindhi Guru Sangat Sabha Association, # 4-1-1236/1/A, King Koti, Abids, Hyderabad-500001.
Ph: 040-23234418 / 19 / 20 / 21, 040 - 24750437
7 All India 1st Ranks in ESE43 All India 1st Ranks in GATE
Authors : Subject experts of ACE Engineering Academy, Hyderabad
While every effort has been made to avoid any mistake or omission, the publishers do not owe any responsibility for any damage or loss to any person on account of error or omission in this publication. The publishers will be obliged if mistakes are brought to their notice through email, for correction in further editions.Email : [email protected]
First Edition : 2011Revised Edition : 2018
Printed at :Rowshni Graphics,Hyderabad.
Price : ₹. 800/- ISBN : 978-1-946581-38-9
ACE Engineering Publications
Sree Sindhi Guru Sangat Sabha Association,# 4-1-1236/1/A, King Koti, Abids, Hyderabad – 500001, Telangana, India.Phones : 040- 23234419 / 20 / 21 www.aceenggacademy.comEmail: [email protected][email protected]
No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, digital, recording or otherwise, without the prior permission of the publishers.
ForewordUPSC Engineering Services in Electrical Engineering
Volume - I Objective Questions: From 1992– 2018
The Stage-I (Prelims) of ESE – 2018 consists of two objective papers. Paper-I is of General
Studies & Engineering Aptitude. Paper-II is of Electrical Engineering of 300 Marks and 3 hours
duration. In stage-II (Mains), the technical syllabus is divided into two papers. The subjects
1. Engineering Mathematics: Matrix theory, Eigen values & Eigen vectors, system of linear equations, Numerical methods for solution of non-linear algebraic equations and diff erential equations, integral calculus, partial derivatives, maxima and minima, Line, Surface and Volume Integrals. Fourier series, linear, nonlinear and partial diff erential equations, initial and boundary value problems, complex variables, Taylor’s and Laurent’s series, residue theorem, probability and statistics fundamentals, Sampling theorem, random variables, Normal and Poisson distributions, correlation and regression analysis.
2. Electrical Materials: Electrical Engineering Materials, crystal structures and defects, ceramic materials, insulating materials, magnetic materials – basics, properties and applications; ferrities, ferro-magnetic materials and components; basics of solid state physics, conductors; Photo-conductivity; Basics of Nano materials and Superconductors.
3. Electric Circuits and Fields: Circuit elements, network graph, KCL, KVL, Node and Mesh analysis, ideal current and voltage sources, Thevenin’s, Norton’s, Superposition and Maximum Power Transfer theorems, transient response of DC and AC networks, Sinusoidal steady state analysis, basic fi lter concepts, two-port networks, three phase circuits, Magnetically coupled circuits, Gauss Theorem, electric fi eld and potential due to point, line, plane and spherical charge distributions, Ampere’s and Biot-Savart’s laws; inductance, dielectrics, capacitance; Maxwell’s equations.
4. Electrical and Electronic Measurements: Principles of measurement, accuracy, precision and standards; Bridges and potentiometers; moving coil, moving iron, dynamometer and induction type instruments, measurement of voltage, current, power, energy and power factor, instrument transformers, digital voltmeters and multi-meters, phase, time and frequency measurement, Q-meters, oscilloscopes, potentiometric recorders, error analysis, Basics of sensors, Transducers, basics of data acquisition systems.
5. Computer Fundamentals: Number systems, Boolean algebra, arithmetic functions, Basic Architecture, Central Processing Unit, I/O and Memory Organization; peripheral devices, data representation and programming, basics of Operating system and networking, virtual memory, fi le systems; Elements of programming languages, typical examples.
6. Basic Electronics Engineering: Basics of Semiconductor diodes and transistors and characteristics, Junction and fi eld eff ect transistors (BJT, FET and MOSFETS), diff erent types of transistor amplifi ers, equivalent circuits and frequency response; oscillators and other circuits, feedback amplifi ers.
Syllabus for Electrical Engineering (EE)
I. Engineering Mathematics
01. Linear Algebra ........................................................................................... 02 - 05
constant T are doubled. Then the new time constant will be (IES-92)
(a) T (b) 2T (c) 4T (d) T / 2 02. In the circuit shown, the V1 and I1 will be (IES-92)
(a) 1 V, 1 A (b) 1 V, 6 A (c) 5V, 5A (d) None of the above. 03. Current having wave form shown is flowing
in a resistance of 10 ohms. The average power is (IES-92)
(a) W1
1000 (b) W2
1000
(c) W3
1000 (d) W4
1000
04. A 24 V battery of internal resistance r = 4 ohm is connected to a variable resistance R. The rate of heat dissipated in the resistor is maximum when the current drawn from the battery is I. The current drawn from the battery will be (I/2) when R is equal to
(IES-92) (a) 8 ohm (b) 12 ohm (c) 16 ohm (d) 20 ohm 05. In the figure shown, if we connect a source
of 2 V, with internal resistance of 1 at AA, with positive terminal at A, then the current through R is (IES-92)
(a) 2 A (b) 1.66 A (c) 1. A (d) 0.625 A 06. In the circuit shown the value of I is
07. When all the resistances in the circuit are of one ohm each, the equivalent resistance across the points A and B will be (IES-92)
(a) 1 (b) 0.5 (c) 2 (d) 1.5 08. A battery is connected to a resistance
causing a current of 0.5 A in the circuit. The current drops to 0.4 A when additional resistance of 5 is connected in series. The current will drop to 0.2 A when the resistance is (IES-92)
(a) 10 (b) 15 (c) 25 (d) 30 09. The current in resistor R shown in figure
will be (IES-92) (a) 0.2 A (b) 0.4 A (c) 0.6 A (d) 0.8 A 10. The equivalent capacitance across ab will be:
(IES-92)
(a) 0.2 F (b) 0.1 F (c) 0.5 F (d) 0 11. Assertion (A): Kirchhoff’s current law is
valid for an ac circuit containing R, L and C. Reason (R): The sum of rms currents at
any junction of the circuit is always zero. (IES-93)
Codes: (a) Both A and R are true and R is the
correct explanation of A (b) Both A and R are true but R is NOT a
correct explanation of A (c) A is true but R is false (d) A is false but R is true
12. In the circuit shown in the figure, the
voltage across the 2 ohm resistor is (IES-93)
(a) 6 V (b) 4 V (c) 2 V (d) zero 13. If a capacitor is energized by a symmetrical
square wave current source, then the steady –state voltage across the capacitor will be a
(IES-93) (a) square wave (b) triangular wave (c) step function (d) impulse function
Which of the above statements are correct? (ESE-18) (a) 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) None of the above
188. A pulse of+10V in magnitude and 2s in
duration is applied to the terminals of a lossless inductor of 1.0H. the current through the inductor would (ESE-18) (a) be a pulse of +20A for the duration of
2s (b) be a pulse of –20A for the duration of 2s (c) increase linearly form zero to 20A in 2s,
and in the positive direction, and, from thereon, it remains constant at +20A
(d) increase linearly form zero to–20A in 2s, and in the negative direction, and, from thereon, it remains constant at –20A
KEY 01. b 02. c 03. c 04. b 05. d 06. b 07. b 08. d 09. a 10. b 11. c 12. c 13. b 14. a 15. a 16. b 17. c 18. d 19. a 20. c 21. d 22. c 23. a 24. d 25. d 26. d 27. c 28. b 29. c 30. c 31. d 32. a 33. c 34. b 35. c 36. a 37. c 38. c 39. a 40. a 41. b 42. b 43. b 44. b 45. a 46. c 47. c 48. b 49. b 50. a 51. d 52. a 53. d 54. c 55. a 56. d 57. a 58. b 59. a 60. b 61. d 62. c 63. c 64.c 65. b 66. a 67. d 68. c 69. c 70. a 71. b 72. d 73. c 74. d 75. a 76. c 77. c 78. c 79. b 80. c
81. b 82. a 83. c 84. a 85. a 86. a 87. c 88. a 89. b 90. d 91. b 92. d 93. a 94. c 95. b 96. d 97. a 98. b 99. d 100. b 101. a 102. d 103. b 104. c 105. b 106. d 107. a 108. b 109. a 110. d 111. b 112. b 113. b 114. d 115. d 116. c 117. a 118. a 119. b 120. c 121. c 122. b 123. c 124. a 125. d 126. b 127. c 128.d 129. a 130. c 131. a 132.c 133. b 134. b 135. b 136. c 137. c 138. c 139. c 140. c 141. b 142.d 143. b 144. d 145. a 146. a 147. c 148. a 149. b 150. a 151. c 152. * 153. d 154. b 155. a 156. b 157. d 158. d 159. b 160. c 161. c 162. d 163. b 164. d 165. * 166. a 167. b 168. b 169. c 170. b 171. d 172. c 173. a 174.d 175. d 176. b 177. d 178. b 179, b 180. a 181, a 182. c 183. d 184. b 185. c 186. b 187. d 188. c
01. Ans: (b) Sol: L N2, R N If N is doubled,
21,
41
2
1
2
1 R
R
L
L
21
21
22
11
2
1
//
//
RR
LL
RL
RL
T
T
New Time constant, T2 = 2 T1 = 2 T 02. Ans: (c) Sol: v(t) across 1 = 5 V i(t) across 1 = 5 A Note that 1 A source has no effect.
The circuit between A, B is simplified as shown in Fig. 1 (star is converted to delta and terminal C is eliminated), and Fig. 2(Terminal D can be eliminated).
5.0
94x
89
23||
43R AB
08. Ans: (d) Sol:
ss VRor
R
VI 25.01
4.052
4.052
s
ss
V
Vor
R
VI
Vs = 0.8 Vs + 2
VVs 102.0
2
R = 20
3 0.2s
x
VI
R R
10 0.2 3020 x
x
RR
09. Ans: (a) Sol: Applying Norton’s theorem to the left and
right of terminals : A, B The circuit is simplified as shown in Fig. 1,
2 and 3.
3
1004 1321 103
RI A
10. Ans: (b) Sol: The equivalent capacitance across a, b is
calculated by simplifying the bridge circuit as shown in Fig. 1 to Fig. 5.
Magnet Moving Coil ammeter is broken then, when connected it will read
(IES-92/13) (a) zero (b) half of the correct value (c) twice the correct value (d) an infinite value. 02. Swamping resistance is a resistance which is
added to the moving coil of a meter to (IES-98)
(a) reduce the full-scale current (b) reduce the temperature error (c) increase the sensitivity (d) increase the field strength
03. An indicating instrument is more sensitive if
its torque to weight ratio is (IES-98) (a) much larger than unity (b) of the order of unity (c) much less than unity (d) made deflection-dependent
04. In a flux meter, the controlling torque is (IES-98)
(a) produced by weights attached to the moving coil
(b) produced by spring (c) not provided at all (d) provided by crossed coil mechanism
05. In a PMMC instrument, the central spring stiffness and the strength of the magnet decrease by 0.04% and 0.02% respectively due to a rise in temperature by 10C. With a rise in temperature of 100C, the instrument reading will (IES-99) (a) increase by 0.2% (b) decrease by 0.2% (c) increase by 0.6% (d) decrease by 0.6%
06. In a permanent magnet moving coil instrument, if the control spring is replaced by another one having a higher spring constant, then the natural frequency and damping ratio will (IES-00) (a) decrease (b) increase and decrease respectively (c) decrease and increase respectively (d) increase
07. What is the correct sequence of the
following types of ammeters and voltmeters with increasing accuracy? 1. Moving iron 2. Moving-coil permanent magnet 3. Induction Select the correct answer using the codes given below: (IES-02)
08. The reflecting mirror mounted on the moving coil of a vibration galvanometer is replaced by a bigger size mirror. This will result in (IES-02) (a) lower frequency of resonance and lower
amplitude of vibration (b) low frequency of resonance but the
amplitude of vibration is unchanged (c) higher frequency of resonance and lower
amplitude of vibration (d) higher frequency of resonance but the
amplitude of vibration is unchanged 09. Consider the following statements
associated with moving iron instruments: 1. These can be used in d.c as well a.c
circuits 2. The scale is non-uniform 3. The moving iron is placed in a field of a
permanent magnet. Which of these statements are correct?
(IES-02) (a) 1, 2 and 3 (b) 1 and 2 (c) 2 and 3 (d) 1 and 3 10. A spring controlled moving iron voltmeter
draws a current of 1mA for full scale value of 100V. If it draws a current of 0.5mA, the meter reading is (IES-02)
(a) 25V (b) 50V (c) 100V (d) 200V 11. Torque/Weight ratio of an instrument
12. Which one of the following materials is used in the fabrication of swamping resistance of a PMMC instruments? (IES-04)
(a) Copper (b)Aluminium (c) Manganin (d) Tungsten 13. Which one of the following is basically a
current sensitive instrument? (IES-04) (a) Permanent magnet moving coil
instrument (b) Cathode ray oscilloscope (c) Electrostatic instrument (d) FET input electronic voltmeter
14. Which one of the following types of
instruments can be used to determine the r.m.s value of ac voltage of high magnitude (10kV) and of any wave shape? (IES-04) (a) Moving iron instruments (b) Dynamometer type instruments (c) Induction instruments (d) Electrostatic instruments
15. Which one of the following statements is
correct? Spiral springs are used in instruments to (IES-04)
(a) provide controlling torque (b) provide damping torque (c) lead the current to moving coil as well as
to provide the controlling torque (d) provide linear deflection
16. Which one of the following decides the time of response of an indicating instrument? (IES-04)
Solutions 01. Ans: (a) Sol: In PMMC meter, current passes through
control springs to the moving coil. These control springs are two in number so if one of them is broken then the current path to the moving coil is disrupted.
No deflecting Torque. Since the other control spring is in good
condition, it will hold the pointer at zero indication.
Here control torque has become half of its original value.
02. Ans: (b) Sol: The temperature error can be reduced by
using swamping resistance. This resistance is an alloy of manganin and copper in the ratio of 20:1.
03. Ans: (a) Sol: When torque to weight ratio is high, the
frictional error in instrument will be less and meter has more sensitivity.
04. Ans: (c) Sol: The current is led into the coil with the help
of a very loose helices of very thin, annealed silver strips. The controlling torque is thus reduced to minimum. But no external mechanism to produce controlling torque.
05. Ans: (a) Sol: If stiffness decreases, then the control torque
also decreases and the meter shows more reading. If strength of the magnet is decreased, then the deflection torque will also decrease, but the meter shows less reading.
For 10oC rise in temperature, decreased stiffness = 0.4% and decreased magnet strength is 0.2%.
Hence the percentage decrease of stiffness is more. Therefore the meter show
0.4% 0.2% = 0.2% more reading. 06. Ans: (b) Sol: Equation of motion in PMMC instrument is
GiKdt
dD
dt
dJ
2
2
Where, 2
2
dt
dJ
= Deflecting Torque
dt
dD
= Damping Torque
K = Control Torque J = Moment of Inertia D = Damping Constant K = Spring Constant G = B.N.A Constant