1. A control system is defined by,

<img src='./qimages/3399-.jpg'>

2. The closed loop transfer function of a control system is For input sin the steady state value of is

<img src='./qimages/3399-2.jpg'>

3. The steady state error due to a step input for type 1 system is

Infinite

Negative

Negligible

Zero

4. The roots of a closed loop characteristic equation for the system shown are

-10





+10

5. The type of the system having transfer function

<img src='./qimages/3399-5.jpg'>









6. The impulse response of the system is

<img src='./qimages/3399-6.jpg'>

7. The overall transfer function for the signal flow graph shown, is <img src='./qimages/3399-7.jpg'>

8. The transfer function for the network shown, is

<img src='./qimages/3399-8.jpg'>

9. The value of function

<img src='./qimages/3399-9.jpg'>

10. The initial slope of the Bode plot gives an indication of

Nature of the system time response

System stability

Gain margin

Type of the system

11. The value of k at which the root locus crosses the imaginary axis, makes the system

Stable

Underdamped

Marginally stable

Unstable

12. For the following characteristic equation, the centroid of the root locus plot is s3+2s2+ks+k=0

0.5

-0.5





13. The transfer function of a system is

If the damping ratio is unity, the value of k is

1 6

1 12

1 24

1 36

14. Let, A the state transition matrix eAt will

<img src='./qimages/3399-14.jpg'>

15. Transfer function of a control system is:

6s +11s 6 the system is

Controllable and observable

Controllable but not observable

Observable but not controllable

neither controllable nor observable

16. The output of a linear system for a unit step input is given by t2.e-t. The transfer function of the system will be









17. The transfer function of the system whose Bode plot is shown, will be

<img src='./qimages/3399-17.jpg'>

10 s

20 s





18. The transfer function has its zero in the right half of the s-plane. The function:­

Is positive real

Will give stable impulse response

Is in minimum phase

Is in non-minimum phase

19. The maximum phase shift that can be provided by a lead compensator with transfer 1+6s function 1+6s/1+2s

15°

45°

30°

60°

20. <img src='./qimages/3399-29.jpg'>

21. <img src='./qimages/3399-29.jpg'>

22. The open loop transfer function of a unity feedback system is G (0.5s The initial slope of Bode plot intersects 0 db line at

w k

k



w

23. The corner frequency for the open-loop transfer function

G H

are

2 rad/sec and 3 rad /sec

rad/sec and route 3 rad /sec

0.25 rad/sec and 0.866 rad/sec

4 rad/sec and route 3 rad/sec

24. The acceptable band of the settling time is

±

10%



Both and depending on applications

25. A unity feedback control system has transfer function its natural frequency will be









26. The frequency, at which the magnitude plot in a Bode plot crosses zero db line, is termed as

Natural frequency

Corner frequency

Phase crossover frequency

Gain crossover frequency

27. As observed from the polar plot shown

<img src='./qimages/3399-27.jpg'>

GM is PM is ve

GM is PM is ve

GM is PM is ve

GM is PM is ve

28. The waveform of the signal 2r(t r(t 4(t can be represented as

<img src='./qimages/3399-28.jpg'>

29. For a second order system, the settling time for ± band is given by

n

n

n

n

30. For the system

<img src='./qimages/3399-30.jpg'>

with u as unit impulse with zero initial state, the output Y is

2e2t

4e2t

2e4t

4e4t

31. An unloaded generator with a pre-fault voltage 1 pu has the following sequence impedances Z0 j 0.15 pu, Z1= Z2= j0.25 pu. The neutral is grounded with a reactance of 0.05 pu. The fault current in pu for a single line to ground fault is

3.75 pu

4.28 pu

6.0 pu

7.25 pu

32. If a voltage-controlled bus is treated as load bus, then which one of the following limits would be violated?

Voltage

Active power

Reactive power

Phase angle

33. In a short transmission line, resistance and inductance are found to be equal and regulation appears to be zero, then the load will be

Unity power factor

Zero power factor

0.707 lagging

0.707 leading

34. Magnetic field intensity of a long conductor carrying current at a distance is

I 4 pie r

I 2 pie r

I 4 pie r

I 2 r

35. If the positive, negative and zero sequence reactances of an element of a power system are 0.3, 0.3 and 0.8 respectively, then the element would be a

Synchronous generator

Synchronous motor

Static load

Transmission line

36. Corona loss is less when shape of the conductor is

Circular

Flat

Oval

Independent of shape

37. Overhead lines generally use

Copper conductors

All aluminium conductors

ACSR conductors

Insulated conductors

38. The economic size of conductor is determined by

Kirchhoff's law

Ohm's law

Kelvin's law

Faraday's law

39. If is the radius of the conductor and the radius of the sheath of the cable. The cable operates stably from the view point of dielectric strength if

r 1.0

r R 1.0

r R 0.632

r R 0.368

40. Which of the following is not a type of insulator used in overhead transmission line?

Rivet type

Pin type

Suspension type

Strain type

41. A bipolar HUDC transmission line has two poles

One positive and other negative

Both Positive

Both negative

None of the above alternatives

42. While building BUS(m x if the added element is a branch, then the new bus impedance matrix will be of dimension

m x m

x m(m

x



43. The main criterion for the design of a distributor is

Voltage drop

Corona loss

Temperature rise

Radio interference

44. Which of the following effect represents increase in resistance due to non-uniform distribution of current in a conductor?

Proximity

Skin

Corona

None of these

45. If the inductance of a line increases, transmission capacity will

Increase

Decrease

Remain same

Independent of inductance

46. Three equal impedances j connected in delta carry a balanced line current of IL. The total active and reactive power drawn by these are

I2R and I2 X respectively

3I2R and 3I2 X respectively

I2R/3 and I2 X/3 respectively

I2X and I2 R respectively

47. If the fault current is 2000A, the relay setting is 50% and CT ratio is 400 then plug setting multiplier will be

25 A

15 A

50 A

10 A

48. A conductor is composed of seven identical copper strands of radius each. What is the self GMD (Geometric Mean Distance) of the conductor?

2.771 r

2.177 r

7.122 r

7.777 r

50. The per unit impedance of a synchronous machine is 0.242. If the base voltage is increased by 1.1 times, the per unit value will be

0.200

0.266

0.242

0.220

51. The critical clearing time of a fault in power systems is related to

Reactive power limit

Transient stability limit

Steady state stability limit

Short-circuit current limit

52. The leakage resistance of a 50 km long cable is 1 M . For a 100 km long cable it will be

1 M

2 M

0.66 M

0.5 M

53. A single phase load of 100 kVA is delivered at 2000V over a transmission line having R=1.4 and X 0.8 . The voltage at the sending end, when the power factor of the load is unity, will be

1.68 kV

2.98 kV

2.70 kV

2.84 kV

54. The breakdown strength at STP is 21 kV/cm. It's breakdown strength at 30°C and 72 cm of Hg. will be

21.25 kV/cm

20.2 kV/cm

23 kV/cm

19.5 kV/cm

55. The coefficient of reflection of voltage for a short circuited line is

1.0

-1.0

0

2.0

56. String efficiency of a suspension insulator string is improved by

longer cross arm

Using discs of different sizes

Using guard ring

Capacitive grading

57. In a n-phase one way convertor, the d.c. output voltage is

<img src='./qimages/3399-57.jpg'>

58. A power station consists of two synchronous generators A B of ratings 250 MVA and 500MVA with inertia 1.6 pu and 1.0 pu respectively on their own base MVA ratings. The equivalent pu inertia constant for the system on 100 MVA common base is

2.6

1.625

0.615

2.0

59. In bundle conductors, if is the Geometric Mean Radius of each sub conductor s and is the bundle spacing as shown in fig. then for the two sub conductor bundle

<img src='./qimages/3399-59.jpg'>

60. In a power system, the maximum number of buses are

PV buses

Slack buses

PQ buses

any of the above

61. In case of dc series motor, it is possible to have finite no-load speed if a resistance is connected across its

Field terminals

Armature terminals

Field and armature together

It is not possible

62. A single phase full bridge diode rectifier delivers a constant load current of 10A. Average and rms values of source current are respectively:­

5A, 10A

10A, 10A

5A, 5A

0A, 10A

63. A power semiconductor may undergo damage due to

High di/dt

Low di/dt

High dv/dt

Low dv/dt

64. A pulse transformer is used in a driver circuit

To prevent dc triggering

To shape the trigger signal

To generate high frequency pulses

To provide isolation

65. A 3-phase delta connected squirrel cage induction motor when started with DOL starter has a starting torque of 600 Nm. Its starting torque when star-delta is used will be

600 Nm

200 Nm

300 Nm

400 Nm

66. In a single phase semiconverter for continuous conduction, each SCR conducts for

alpha







67. A chopper, whose voltage as well as current remain negative, is known as

Type-A

Type-B

Type-C

Type-D

68. In order to eliminate the fifth harmonic voltage from the phase voltage of an alternator, the coil should be pitched by

72°

36°

15°

18°

69. The power required by the pump from the motor is proportional to

(Speed)2

(Speed)3

(Speed)

(Speed)1/2

70. The normal voltage used for dielectric heating is

1500 V

15 kV

30 kV

33 kV

71. A single-phase full wave convertor is connected across 250V ac. Its output voltage when firing angle is 30° will be

195 V

210 V

215 V

250 V

72. For heating magnetic materials using induction heating, eddy current and hysterisis losses are respectively proportional to

f 2 and f

f and f 2

f 2 and f 2

None of the above

73. At low values of slip the torque of a 3-phase induction motor is



T alpha s

T s-1

T s2

74. The rotor of a 3-phase, 4 -pole, 50 Hz induction motor is rotating at 1440 r.p.m. The value of induced rotor current frequency will be

0 Hz

1 Hz

2 Hz

50 Hz

75. In a 3-phase induction motor, the ratio of air-gap power, rotor copper losses and developed mechanical power is respectively

s 1

1 s

s 1

1 s

76. If the transformer frequency is changed from 50 Hz to 60 Hz, the ratio of eddy current loss at 60 Hz to 50 Hz at constant voltage will be

5 6

6 5

25 36

36 25

77. Which test is performed to determine core loss at full load of a transformer?

Short circuit

Sumpner

Open circuit

None of these

78. For 100% excitation in synchronous motor, the relationship between back emf E and applied voltage V is

E V

E V

E V

E V

79. The power factor of the input power to a synchronous motor is adjusted by adjusting

Magnitude of excitation

Magnitude of armature reaction

Number of poles

None of these

80. A balanced 3-phase, star connected load of 120 kW takes a leading current of 100A with a line voltage of 866V, 50 Hz. The impedance of the load per phase is

4 j3 ohms

4 -j3 ohms

3 j4 ohms

3 j4 ohms

81. The maximum efficiency of a 200 kVA transformer having an iron loss of 1800 W and full load copper loss of 3200 W occurs at

100 kVA

150 kVA

200 kVA

125 kVA

82. In a three phase induction motor, the ratio of starting current to full load current is 12.56 and the ratio of starting torque to full load torque is 1.6. Percentage slip at full load is

0.01%

12.64%



None of these

83. Skew is used in induction motors in order to reduce torque due to

Time harmonics

Slot harmonics

Space harmonics

Reverse rotating fields

84. Two identical loss less series motors connected in series across a DC supply voltage run at speeds of N1 and N2. The ratio of their output will be

N2 2 N1 2

N1: N2

N2 N1

1 1

85. A 400V DC shunt motor takes a current of 5.6 A on no-load and 68.3A on full load. Armature reaction weakens the field by 3%. For Ra= 0.18 brush voltage drop of 2V and Rf= 200 the ratio of full load speed to no-load speed will be

0.0

0.94

1.00

3.64

86. In a 3-phase induction motor working at full load, the torque is related with slip and supply voltage V as follows o2V 2

TV s

T s2v02



T alpha sV02

87. Field control of a DC shunt motor gives

Constant kW drive

Constant torque drive

Constant speed drive

Variable load speed drive

88. A 2-phase, 4-pole permanent magnet stepper motor has a step of

90°

45°

30°

22

89. In hand tool applications, the single-phase motor used is

ac series motor

Shaded pole motor

Capacitor start motor

Capacitor run motor

90. The emf per turn for a single phase 2200/220 50 Hz transformer is approximately 12V. The number of primary and secondary turns are

18, 183

183, 18

155, 26

172, 21

91. Which of the following motors is preferred when quick speed reversal is the main consideration?

Squirrel cage induction motor

Wound rotor induction motor

Synchronous motor

D.C. motor

92. In a DC machine, the angle between the stator and rotor fields is

Dependent upon the load

45°

90°

180°

93. If stator impedance is neglected, the maximum torque in an induction motor occurs at a rotor resistance of

x2

x2

sx2

x2

94. A 6 pole, wave connected DC armature has 250 conductors and runs at 1200 rpm. The emf generated is 600V. The useful Flux/pole is

0.04 Wb

0.4 Wb

4.0 Wb

0.44 Wb

95. A single phase, 2000V alternator has armature resistance and reactance of 0.8 and 4.94 respectively. The voltage regulation of the alternator at 100A load at 0.8 leading power factor is





14%



96. In a 3-phase induction machine the slip rings of the machine are open-circuited. The frequency of the voltage across the slip rings is 75 Hz. The rotor is driven at a speed of

750 rpm

1500 rpm

2250 rpm

3750 rpm

97. Maximum torque in 3-phase induction motor varies as

f

1 f

1 f 2

1 f 3

98. A pole pitch in electrical machines is

180° electrical

180° electrical

180° mechanical

180° electrical

99. In a single-phase transformer the magnitude of leakage reactance is twice that of resistance of both primary and secondary. With secondary short circuited, the input power factor is



route 5

route 5

1/3

100. A DC series motor drawing an armature current of I is operating under saturated magnetic a conditions. The torque developed in the motor is proportional to

1 Ia

1 Ia2

Ia2

Ia

101. A megger is used for measurement of

Low valued resistance

Medium valued resistance

High valued resistance (Generaly insulation resistance)

All of the above

102. VAh metering can be done by using

A ball and disc friction gearing

Trivector meter

Bridge connected rectifier

All of the above

103. A 100 µ A ammeter has an internal resistance of 100 . For extending its range to measure 500 the shunt resistance required is

20

22.22

25

50

104. Measurement of power of a 3-phase balanced load is done using two wattmeter method. If the ratio of the wattmeter readings is 2 1 then power factor of the circuit will be

0.0

1.0

0.5

0.866

105. Capacitive transducers are normally used for

Static measurements

Dynamic measurements

Both static and dynamic measurements

Transient measurements

106. Which of the following is not a type of wattmeter?

Moving coil permanent magnet

Induction

Dynamometer

Electrostatic

107. At high frequency the accuracy of all measuring meters

Increases

Decreases

Remains the same

Depends upon the type of meter

108. The sensitivity of a PMMC instrument is 10k /V. If this instrument is used in a rectifier type voltmeter with half wave rectification, the sensitivity will be

10 k

9 k

4.5 k

2.2 k

109. A voltmeter has a resistance of 2000 . When it is connected across a DC circuit, its power consumption is 2 mW. Suppose this voltmeter is replaced by a voltmeter of 4000 resistance, the power consumption will be

1 mW

2 mW

4 mW

8 mW

110. Frequency can be measured by using

Maxwell's bridge

Schering bridge

Heaviside Campbell bridge

Wien's bridge

111. A null-type of instrument as compared to a deflecting type instrument has

A higher capacity

A lower sensitivity

A faster response

All of these

112. A Watt meter has a full scale range of 2500 Watt. It has an error of of true value. What would be the range of reading if true power is 1250 Watt?

1225 Watt 1275 Watt

1245 Watt 1255 Watt

1200 Watt 1300 Watt

1237.5 Watt 1262.5 Watt

113. Electrostatic type instruments are primarily used as

Ammeters

Wattmeters

Voltmeters

Ohmmeters

114. In an Induction type meter, maximum torque is produced when the phase angle between two fluxes is

0°

45°

60°

90°

115. The burden of current transformer is expressed in terms of

Secondary winding current

VA rating of transformer

Voltage, current and power factor of secondary winding

None of these

116. An Acquadag is used in a CRO to collect

Primary electrons

Both

Secondary emmission electrons

None of these

117. The permanent magnet in an a.c. energy meter provides

Damping torque

Deflecting torque

Breaking torque

All of these

118. Creeping in a single-phase induction type energy meter may be due to

Overcompensation for friction

Over voltages

Vibrations

All of these

119. The inductance of a high Q inductor can be measured using a

Hay's bridge

Schering bridge

Wein's bridge

Maxwell bridge

120. For wire wound strain gauges, the gauge factor is defined as



1+2 delta R/R

1+2V



121. The impedance of parallel resonating circuit would be

Zero

Maximum

Minimum

Infinite

122. The imaginary part of admittance is called

Resistance

Reactance

Susceptance

Conductance

123. Inverse fourier transform of Q is



1

1 2

u

124. The parameter y12of the following two port network is



a

yb

-yb

125. The time constant of the network shown below, is

2RC/3

RC

3 RC

2 RC

126. A series RLC circuit is in resonance at 100 Hz. If capacitance is made four times, the resonant frequency will be

50 Hz

100 Hz

200 Hz

400 Hz

127. In an underdamped parallel RLC network, the time constant associated with the decaying sinusoid oscillation is

1

2RC

1

L C

128. Two circuits having the same magnitudes of impedances are joined in parallel. The power factor of one circuit is 0.8 and of other is 0.6 .The power factor of the combination is

0.6

0.75

0.7071

0.8

129. When maximum power transfer takes place, the efficiency of power transfer of the circuit

25%

50%

75%

100%

130. Thevenin's theorem cannot be applied to networks that contain elements which are

Active

Passive

Linear

Non-Linear

131. The peak value of cos wt sin is

1





route 3

132. A parallel RLC circuit is fed at a frequency of . rad/sec such that . The power factor of the circuit is

Zero

Unity

Leading

Lagging

133. At a particular instant an inductance of 1H carries a current of 2A while the voltage across it is 1V. The energy stored in the inductance in Joules is

1 2

1

3 2

2

134. If the transform of

<img src='./qimages/3399-134.jpg'>

135. <img src='./qimages/3399-135.jpg'>

136. In a LTI system impulse response is Find the input if the output 2 delta





1/2

1/2

137. The steady state response for the signal cos(2t) of the system with transfer function will be

<img src='./qimages/3399-137.jpg'>

138. The laplace transform of shifted unit step function

<img src='./qimages/3399-138.jpg'>

139. The even part of a function Sin is given as

Cos

Cos

1/2 Sin

1/2 Sin

140. In a series RL circuit R=20 O L=0.1H and frequency is 50Hz. The impedance of the circuit would be doubled by making the value of R

40

52.6

67.5

72.5

141. A low pass RC circuit has VR= 12V and V c 5 V . The supply voltage is

7 V

7 V

17 V

13 V

142. In terms of ABCD parameters, a two port network is symmetrical if and only if

A B

B C

C D

D A

143. For the circuit shown, the reading in ammeter A1, when A2 and A3 show 12A and 9A respectively, is

<img src='./qimages/3399-144jpg'>
3

6

2 3

1 6

145. A voltage waveform V(t)=12t2 is applied across 1H inductor for t 0,with initial current through it being zero. The current through inductor for t 0 will be

4 t3

12 t 3

24 t

12 t

146. If Q of a coil is increased, its power factor will

Decrease

Increase

Remains same

None of these


147. A balanced star connected load of 8 j6 ohms per phase is connected to a 3-phase 230V supply. Power being consumed by the load is

1410.67 W

1269.6 W

4232 W

2443.35 W

148. Thevenin's equivalent voltage and resistance for the circuit shown, when R2 is considered as the load resistance, are

7 V and 0 O

21 V and 7

28 V and 0

7 V and 7

149. The characteristic equation of the series RLC circuit is

s2 s R L 0

s2 s R L 0

s2 s LC 0

s2 R/L 1/LC 0

150. If Norton's motor is applied to find the current in resistance RL as shown below. The Norton's equivalent current and resistance will be 2• 2•

<img src='./qimages/3399-150.jpg'>

10A and 1 mew respectively

15A and 1 respectively

15A and 4 respectively

10A and 4 respectively

151. The reflection coefficient for the transmission line at is

1

1

0

0.5

152. The flux density at a point in space is given by

4xâx +2ky ay +8âz Wb/m2

The value of constant must be equal

2

-0.5

0.5



153. Line charge is given by which of the following

Maxwell Equations

Gauss law

Faraday's law

Ampere's law

154. A circular loop has its radius increasing at a rate of 2 m/s. The loop is placed perpendicular to a constant magnetic field of 0.1 Wb/m2. When radius of the loop is 2m, the emf induced in the loop will be

0.8 V

0.4 V

0.2 V

0 V

155. The intrinsic impedance of a lossy dielectric medium is given by

<img src='./qimages/3399-155.jpg'>

156. An electric field on a plane is described by its potential

V 20 r where is the distance from the source. The field is due to

a monopole

a dipole

Both a monopole and a dipole

A quadrupole

157. Which of the following potential does not satisfy Laplace's equation

V 10 xy

V 10 /pie

V f.Cos 10

V P.Cos

158. Maxwell's divergence equation for the electric field is . ..E

<img src='./qimages/3399-158.jpg'>

159. The depth of penetration in a lossy dielectric increases with increasing

Conductivity

Permeability

Wavelength

Permittivity

160. The electric flux inside a conducting sphere is

Zero

Uniform

Minimum

Maximum

161. Point form of Ohm's law is represented by the relation s

<img src='./qimages/3399-161.jpg'>

162. The forward resistance of the diode shown in figure is 5 O . The dc component of the source current is

<img src='./qimages/3399-162.jpg'>

163. Frequency of oscillation of Colpitts oscillator is given by

<img src='./qimages/3399-163.jpg'>

164. The type of power amplifier which exhibits crossover distortion in it's output is

Class A

Class B

Class C

Class AB

165. For audio applications, which of the following is most common oscillator

Crystal Oscillator

LC oscillator

RC oscillator

None of these

166. A three phase current source inverter can be operated in

30 degree or 90 degree mode

0 degree or 60 degree mode

60 degree or 120 degree mode

120 degree or 180 degree mode

167. A digital to analog converter with full scale output voltage of 3.5 V has a resolution close to 14 mV. Its bit size is

32

16





168. The peak inverse voltage of a full wave bridge rectifier is

V m 2

2 vm

2 V m 3

V m

169. Negative feedback used in amplifier results in

More gain, more bandwidth

More gain, less bandwidth

Less gain, more bandwidth

Less gain, less bandwidth

170. The Ebers-Moll model is applicable to

Unipolar junction transistor

Bipolar junction transistor

NMOS transistor

Junction field effect transistor

171. In the zener diode network shown below, the power P dissipated by the zener diode is Z R

<img src='./qimages/3399-171.jpg'>
0 W

7.27 W

8.73 W

10 W



172. In common emitter configuration of n p n transistor

ß IC IB



Both and

None of and

173. In order to make a 2-bit adder following is required

One full and one half adder

One full adder

Two half adders

One half adder

174. A linear system with system function 1 s is excited with unit step input. The output for t 0 is given by



1

t

t2

175. The characteristic equation of a feedback control system is 2s4+s3+3s2+5s+10 0. The number of roots in the right half s-plane are:­

3

2

1

Zero

176. Which of the following point is not on the root locus of a system having open loop transfer function

s j 1.732

s

s 1.5

s

177. Which of the following is not the property of state transition matrix

I







178. In the signal flow graph shown below, the number of forward paths and the number of individual loops are respectively:­

2 and 5

1 and 7

2 and 6

2 and 7

179. <img src='./qimages/3399-179.jpg'>

180. <img src='./qimages/3399-180.jpg'>