Assistant Engineer Question Paper 2008

1) Thyrites are used for protection against
a. corona
b. surge current
c. damping
d. over current
2) The capacitance connected between the I/P and O/P of an amplifier affects its high frequency response due to
a. COLPIT effect
b. MILMAN effect
c. COLLINS effect
d. MILLER effect

3) For rural electrification in a country like India with complex network it is preferable to use
a. MOCB
b. Vacuum CB
c. Oil CB
d. Air break CB

4) Modulation is a process to vary
a. none of the these
b. Carrier signal by the signal to be transmitted
c. Signal to be transmitted
d. Signal to be transmitted as well as to vary carrier signal by the signal to be transmitted

5) The major application of Zener diode is
a. Voltage regulation
b. Chopper
c. Amplifier
d. Rectifier

6) KVL states that the algebraic sum of the voltage drop around a closed loop in an electric circuit is
a. equal to 2
b. equal to zero
c. equal to 1
d. equal to the input voltage

7) Which one of the following is not related to modems?
a. DCE
b. data phone
c. data-set
d. Telephone

8) The value of coefficient of coupling is always
a. none of the above
b. greater than 1
c. equal to 1
d. less than 1

9) The roots of the characteristic equation are called
a. Zeroes
b. Poles
c. Eigen values
d. Eigen vectors

10) Silicon devices are used for high temperature application compared to germanium because
a. silicon is more thermally stable
b. reverse saturation current is less in silicon
c. silicon can dissipate more power
d. none of the above

11) The ASCII code is
a. 9 bit code
b. 7 bit code
c. 5 bit code
d. 11 bit code

12) Star delta starter is used for starting
a. Squirrel Cage Motor with delta connected stator winding
b. DC Motor
c. Synchronous motor
d. Universal Motor

13) An automatic iron box is an example of
a. a single feedback control system
b. an open loop control system
c. none of the these
d. a multi feedback control system

14) Transmission lines are transposed to
a. reduce copper loss
b. reduce skin effect
c. prevent interference with neighbouring telephone lines
d. prevent short-circuit between any two lines

15) What is the value of modulation index in AM?
a. above 1
b. between 0 and 1
c. between -1 and 0
d. above 100

16) Steady state stability of a power system is improved by
a. decreasing generator inertia
b. reducing fault clearing time
c. using double circuit line
d. single pole switching

17) The voltage gain of an emitter follower is always
a. less than 1
b. more than 1
c. greater than or equal to 1
d. 1

18) The rms value of sine wave is
a. 0.707
b. 0
c. 0.5
d. 1

19) The most important part of an operational amplifier is
a. Adder
b. Substractor
c. Integrator
d. Differential amplifier

20) A + AB is equal to
a. A
b. A + B
c. B
d. AB

21) A cache in a computer is
a. none of the above
b. used to improve the storage capacity
c. used to hold more date
d. used to increase the speed of execution

22) In an EXCLUSIVE-OR gate, when the O/P is zero, the inputs are
a. 1,1
b. 1,0
c. 0,1
d. 1,x

23) The transfer function is defined for
a. All of the above
b. Linear and time-variant system
c. Non-linear and time-variant system
d. Linear and time-invariant system

24) Donor type impurities
a. create excess free electrons
b. have five valence electrons
c. all of the above
d. used to make n-type semiconductors

25) When the supply frequency is decreased the capacitive reactance
a. increases
b. decreases
c. remains the same
d. unpredictable

26) When resonance occurs in a circuit, the pf is
a. 1
b. greater than 1
c. 0
d. less than 1

27) A series circuit containing passive elements has the following voltage and current
v = 100 sin (314t + 50 ) and
i = 4 cos (314t + 13 ).
The circuit elements
a. could be either R and C or R, L and C
b. must be L, C and R
c. must be R and C
d. must be R and L

28) A CLASS C power amplifier is one in which the operating point is chosen such that the output current
a. always flows
b. zero for more than one half of I/P cycle
c. never flows
d. zero for less than one half of I/P cycle

29) The outstanding characteristic of a direct coupled amplifier is its
a. ability to amplify DC and low frequency signals
b. avoidance of frequency sensitive components
c. temperature stability
d. economy

30) When a 3-phase synchronous motor is running at synchronous speed, the damper winding produces
a. Torque aiding developed torque
b. Damping torque
c. Eddy current torque
d. Zero torque

31) Which one of the following is not a method of power generation?
a. Thermal
b. CHD
c. MHD
d. Hydroelectric

32) For stability and economic reasons we operate the transmission line with power angle in the range
a. 10° to 25°
b. 65° to 80°
c. 60° to 75°
d. 30° to 45°

33) Ferranti effect is experienced on long transmission lines when it is
a. lightly loaded
b. all of the above
c. on full load at 0.8 pf lag
d. on full load at upf

34) The gain of the amplifier is usually expressed in
a. Volts
b. mho
c. Amperes
d. Decibels

35) www stands for
a. World wide weight
b. Wide world weight
c. Wide world web
d. World wide web

36) A dc cumulatively compounded motor delivers rated torque at rated speed. If the series fields is short circuited then the armature current and speed will
a. increase and decrease respectively
b. both decrease
c. decrease and increase respectively
d. both increase

37) Which one of the following is a synchronous optical network ?
a. SONET
b. TELNET
c. INTERNET
d. DELNET

38) Micro-programming is a technique for
a. writing small programs
b. programming the microprocessors
c. programming the control steps of a computer
d. programming input and output

39) The number of flip flops required in a decade counter is
a. 2
b. 10
c. 3
d. 4

40) A 3-phase synchronous motor is operating at a load angle of 20° and with excitation voltage equal to the applied voltage. The synchronous reactance drop in terms of excitation voltage
a. 38.2%
b. 34.73%
c. 69.46%
d. 32.9%

41) The collector current of transistor is always
a. none of the above
b. greater than emitter current
c. less than emitter current
d. equal to emitter current

42) Base modulation is used in TV transmission because
a. Power required is small
b. All of the above
c. High degree of linearity
d. Large power O/P and better efficiency

43) A resistance is connected in series with an inductive coil. The phase difference between the current and applied voltage
a. none of the above
b. increases with increase in supply frequency
c. decreases with increase in frequency
d. remains constant

44) Rise time of an under damped system is
a. Time taken by the response to reach 50 %
b. time taken by the response time to rise from 0 to 100%
c. time taken by the response to reach 95%
d. None of the above

45) Which of the following is used for serial access storage only?
a. RAM
b. Core memory
c. Magnetic tape
d. Maganetic disk

46) Which amplifier configuration has the lowest output impedance ?
a. CO
b. CB
c. CC
d. CE

47) Superposition theorem is applicable only for circuits which are
a. Non-linear
b. Bilateral
c. Linear
d. Linear and Bilateral

48) The following protocol is used used for accessing web pages
a. SMTP
b. PTTP
c. HTTP
d. FTP

49) For a given cross-sectional area of transformer core, stepped cores are used
a. to reduce the core loss
b. to reduce the magnetizing current
c. to provide more mechanical strength to the core
d. to reduce the conductor material

50) While finding the Thevenin equivalent circuit between two terminals, Vth is equal to
a. Net voltage available in the circuit
b. emf of the battery nearest to the terminals
c. Short circuit terminal voltage
d. Open circuit terminal voltage

51) The peak overshoot of a second order system is
a. is zero
b. independent on damping ratio
c. depends on damping ratio
d. is a constant

52) Input impedance of a transmission line at any distance from the load can be determined using
a. Ben chart
b. Smith chart
c. none of the above
d. Gant chart

53) The surge impedance of 50 km long underground cable is 50 ohms. For a 25 km length it will be
a. 25
b. 100
c. 50
d. 75

54) A voltmeter gives 120 oscillations per minute when connected to the rotor of an induction motor. When the stator frequency is 50Hz, slip of the motor is
a. 4%
b. 2%
c. 5%
d. 2.5%

55) An ideal OP-AMP has
a. infinite bandwidth
b. all of the above
c. infinite gain
d. infinite input impedance

56) A 3-phase synchronous generator is operating at constant load while the excitation is adjusted to give unity pf current. If the excitation is now increased the pf will become
a. Unity
b. Leading
c. Lagging
d. Zero

57) The residual magnetism of a self-excited dc generator is lost. To build up its emf again
a. the field winding connection must be reversed
b. field winding should be excited by low voltage DC voltage
c. its armature connection must be reversed
d. the fieldd winding must be replace

58) A 3-phase breaker is rated at 2000 MVA, 33 kV. Its making current will be
a. 89 kA
b. 35 kA
c. 49 kA
d. 70 kA

59) While drawing the phasor diagram of a parallel circuit, which one is taken as the reference
a. Voltage
b. Current
c. Power
d. None of the above

60) The impulse ratio of a rod gap is
a. between 1.2 and 1.5
b. between 1.6 and 1.8
c. 1
d. between 2 and 2.2

61) Which one of the following is not an image file format ?
a. image.pdf
b. image.bmp
c. image.jpg
d. image.png

62) When two capacitors C1 and C2 are connected in series, the equivalent value of capacitance is
a. C1C2
b. C1C2/(C1 + C2)
c. C1 + C2
d. C1 – C2

63) How many layers are available in OSI ?
a. 4
b. 6
c. 5
d. 7

64) Which one of the following devices is not used for networking ?
a. Cub
b. Hub
c. Switch
d. Router

65) While measuring power in a three phase circuit using two wattmeters, one of the meter reads zero when
a. when the pf is 0.5
b. pf is zero
c. pf of the circuit is 1
d. pf is 0.6

66) The transfer function of a system is given by T(S) = K/[ s³(1+sT) ]. The type and the order of the system are
a. 3 and 3
b. 3 and 2
c. 3 and 4
d. 2 and 3

67) PUSH and POP operations are connected with
a. ALU
b. MEMORY
c. PROCESSOR
d. STACK

68) An instantaneous change in voltage is not possible in
a. an inductor
b. a capacitor
c. resistor
d. a current source

69) The full scale input voltage to an ADC is 10V. The resolution required is 5mV. The minimum number of bits required for ADC is
a. 11
b. 8
c. 12
d. 10

70) Which instrument is used to measure low values of resistance ?
a. Anderson Bridge
b. Wheatstone Bridge
c. Kelvin Double Bridge
d. Maxwell Bridge

71) Which of the following terms is not associated with a sample and a hold circuit?
a. Acquisition time
b. Aperture time
c. Conversion time
d. Sample mode

72) Two devices commonly used to generate light for fiber optic communication system
a. All of the above
b. LED and TFT
c. LED and ILD
d. LED and LCD

73) The form factor is the ratio of
a. rms value to average value
b. average value to rms value
c. peak value to rms value
d. peak value to average value

74) The zero point characteristics for the Potier diagram can be obtained by loading the alternator using
DC motor
Water load
Lamp load
Synchronous motor

75) The phase shift between the output and input of a CE amplifier configuration is
a. 180°
b. 270°
c. 90°
d. 360°

76) How many state equations are required to represent a system described by a third order differential equation ?
a. 3
b. 4
c. 2
d. 2

77) BJT can be used in the following mode for amplification applications
a. CC
b. CB
c. CE
d. All of the above

78) In a computer program, the process of executing the same instruction over and over is called
a. Branching
b. Circulating
c. Looping
d. None of these

79) For maximum transfer of power, internal resistance of the source should be
a. Zero
b. less than load resistance
c. more than load resistance
d. equal to the load resistance
80) The CPU of a computer consists of
a. ALU and Control Unit
b. Memory and ALU
c. INPUT and OUTPUT Unit
d. None of the above

81) The following mark up is used for creating webpages
a. PASCAL
b. HTML
c. COBOL
d. HTPP

82) The specification for a standard 74 series TTL gate reads propagation delay as 33ns and power dissipation is 1mV. This circuit is
a. Standard Schottky TTL
b. High speed TTL
c. Low speed TTL
d. Low power Schottky TTL

83) Which region of the transistor characteristic is used for amplification
a. cut off
b. active
c. saturation
d. passive

84) Power in a single phase circuit can be measured
a. using all the above 3 methods
b. using 3 volltmeters
c. using one wattmeter
d. using 3 ammeters

85) The decimal equivalent of binary 10111 is
a. 16
b. 23
c. 20
d. 4

86) Which one of the following power semiconductors can be turned on and turned off using the gate ?
a. Power transistor
b. Power MOSFET
c. SCR
d. GTO

87) For a closed loop system to be stable, the poles of the CLTF must lie
a. on the left half of the S plane
b. at the origin
c. on the right half of the S plane
d. none of the above
88) The energy stored in the magnetic field is given by
a. 1/2 LI²
b. 1/2 LV²
c. 1/2 L²V²
d. 1/2 L²I²

89) Transformer cores are laminated to reduced
a. Hysteresis loss
b. Eddy current loss
c. Both eddy current and hysteresis loss
d. Ohmic loss

90) The most commonly used detector in AM receiver is
a. Ratio detector
b. Envelope detector
c. Discriminator
d. Coherent detector

91) Three identical impedances are connected in delta to a 3-phase supply of 400 Volts. The line current is 34.65 A and the total power taken is 14.4 kW. The resistance of the load in each phase is
a. 12 ohms
b. 16 ohms
c. 10 ohms
d. 20 ohms

92) A computer can execute only programs written in
a. High level language
b. Machine language
c. Assembly language
d. None of the above

93) The insulation of modern EHV line is designed based on
a. Switching voltage
b. RI
c. Corona
d. Lightning voltage

94) An amplifier can be converted to an oscillator using
a. null feedback
b. negative feedback
c. zero feedback
d. positive feedback

95) Which amplifier configuration is used by a push-pull configuration
a. Class AB
b. Class B
c. Class C
d. Class A

96) An analog computer used for resolving a vector into two mutually perpendicular components has a device called
a. Register
b. Resolver
c. Subroutine
d. None of these

97) Main disadvantage of FM is
a. Low operating voltage
b. Complex circuits
c. Adjacent channel interferrence
d. Limited line of sight range

98) The Hall effect voltage in intrinsic silicon
a. is negative
b. is zero
c. is positive
d. changes sign on application of magnetic field

99) Which one of the following is not a power semiconductor device ?
a. GTO
b. CRS
c. IGBT
d. SCR

100) Which of the following is not a programming language ?
a. EIFFEL
b. ALGOL
c. SUSE LINUX
d. ADA