ELECTRONICS AND TELECOMMUNICATION ENGINEERING
ELECTRONICS AND TELECOMMUNICATION ENGINEERING SYLLABUS
(These syllabus may change from time to time. Please check with the relevant Public Service Commission websites for any changes in the syllabus)
PAPER I 1. Materials and components Structure and properties of Electrical Engineering materials Conductors, Semi‐conductors and Insulators, Magnetic, Ferroelectric, piezoelectric Ceramic, Optical and Superconducting materials. Passive components and characteristics Resistors, Capacitors and Inductors : Ferrites, Quartz crystal. Ceramic resonators, Electromagnetic and electro‐mechanical components. 2. Physical Electronics, Electron Devices and ICs Electrons and holes in semi‐conductors. Carrier Statistics, Mechanism of current flow in a semi‐conductor, Hall effect. Junction theory; Different types of diodes and their characteristics; Bipolar Junction transistor; Field effect transistors; Power switching devices like SCRs. CTOs, power MOSFETs; Basics of ICs‐bipolar, MOS and CMOS types; Basics of Opto‐Electronics. 3. Signals and Systems Classification of signals and systems; System modelling in terms of differential and difference equations; State variable representation; Fourier series; Fourier transforms and their application to system analysis; Laplace transforms and their application to system analysis; Convolution and superposition integrals and their applications; Z‐transforms and their applications to the analysis and characterisation of discrete time systems; Random signals and probability. Correlation functions; Spectral density; Response of linear system to random inputs. 4. Network Theory Network analysis techniques: Network theorems, transient response steady state sipusoidal response; Network graphs and their applications in network analysis; Tellegen’s theorem. Two port networks : Z, Y, h and transmission parameters. Combination of two ports analysis of common two ports. Network functions; parts of network functions; obtaining a network function from a given part. Transmission criterion : dalcy and rise time. Elmorc’s and other definition effect of cascading Elements of network synthesis. 5. Electromagnetic Theory Analysis of electrostatic and magnetostatic fields; Laplace’s and Potson’s equations; Boundary value problems and their solutions; Maxwell’s equations : application to wave propagation in bounded and unbounded media; Transmission lines : basic theory, standing wave, matching applications microstrip lines; basics of waveguides and resonators; Elements of antenna theory. 6. Electronic Measurement and Instrumentation Basic concepts standards and error analysis; Measurements of basic electrical quantities and parameters; Electronic measuring instruments and their principles of working, analog and digital, comparison characteristics, applications Transducers; Electronic measurements of non‐electrical quantities like temperature, pressure, humidity etc. Basics of telemetry for industrial use. PAPER II 1. Analog Electronic Circuits Transistor biasing and stabilization small signal analysis. Power amplifiers Frequency response. Wide banding techniques Feedback amplifiers Tuned amplifier? Oscillators, Rectifiers and power; supplies Op Amp PLL other linear integrated circuits and applications Pulse shaping circuits and waveform generator. 2. Digital Electronic Circuits Transistor as a switching element; Boolean algebra simplification of Boolean functions, Karnaugh man and applications’ IC Logic gates and their characteristics : IC logic families : DTL, TTL, ECL, NMOS PMOS and CMOS gates, and their comparison Combinational logic circuits; Half adder Full adder. Digital compartor. Multiplexer. Demultiplexer; ROM and their applications, Flipflops, R‐S, J. K., D and T np‐nops; Different types of counters and resisters; Waveform generators. A/D and D/A conveners. Semi‐conductor memories. 3. Control Systems Transient and steady state response of control systems, Effect of feedback on stability and sensitivity; Root locus techniques; Frequency response analysis Concepts of gain and phase margins; constant‐M and Consta. N Nichols’s Chart; Approximation of transient response from Constant‐N nichols Chart; Approximation of transient response from closed loop frequency response; Design of Control systems Compensators; Industrial controllers. 4. Communication Systems Basic information theory. Modulation and detection in analogue and digital systems; Sampling and data reconstruction Quantization & Coding; Time division and frequency division multiplexing, Equalisation; Optical Communication in free space and fibre optic; Propagation of signals at HF, VHP, UHF and microwave frequency; Satellite Communication. 5. Microwave Engineering Microwave Tubes and solid state devices, Microwave generation and amplifiers, Waveguides and other Microwave Components and Circuits Microstrip circuits, Microwave Antennas, Microwave Measurements, Masers Lasers; Microwave propagation. Microwave Communication systems‐terrestrial and Satellite based. 6. Computer Engineering Number Systems; Data representation; Programming; Elements of a high level programming language PASCAL/ C. Use of basic data structures; Fundamentals of computer architecture; Processor design; Control unit design; Memory organisation. I/o System Organisation, Micro‐processors : Architecture and instruction set of micro‐processors 8085 and 8086. Assembly language programming. Micro‐processor based system design : typical examples. Personal computers and their typical uses. 
Recommended Books1. Signals and Systems by Kumar
2. Power Electronics by P.S. Bimbhra 3. The Art of Electronics Text Book (CLPE) by Horowitz 4. Electronic Principles (SIE) by Albert Malvino 5. Electronic Devices and Circuits by David A. Bell 6. Solid State Electronic Devices by Streetman

ELECTRONICS AND TELECOMMUNICATION STUDYMATERIALS
1. Study Materials contributed by Mercy Benyl Page 1
2. Study Materials contributed by Mercy Benyl Page 2
3. Study Materials contributed by Mercy Benyl Page 3
4. Study Materials contributed by Mercy Benyl Page 4
5. Study Materials contributed by Mercy Benyl Page 5
1:The main constituents of a Portland Cement is
A:lime
B:Alumina
C:Iron Oxide
D:Alkalies
Ans: A
2:The most commonly used bond for all wall thickness is
A:Flemish bond
B:English bond
C:Stretching bond
D:Heading bond
Ans: B
3:A line normal to the plumb line at all points is known as
A:Horizontal line
B:Vertical line
C:Level line
D:Line of the collimation
Ans: C
4:In a wellconditioned triangle, no angle should be less than
A:30°
B:45°
C:60°
D:90°
Ans: A
5:A fixed point of reference of known elevation is called
A:Change point
B:Station point
C:Bench mark
D:Datum
Ans: C
6:The part which controls the air fuel ratio in a petrol engine is
A:Injector
B:Carburettor
C:Governor
D:None of the above
Ans: B
7:In IC Engines the process of removing burnt gases from combustion chamber of cylinder is known as
A:Supercharging
B:Polymerisation
C:Scavenging
D:Detonation
Ans: C
8:The compression ratio of Diesel engine varies from
A:15 to 25
B:10 to 15
C:6 to 10
D:25 to 40
Ans: A
9:The purpose of moderator in a nuclear power plant is
A:To moderate the radioactive pollution
B:To control reaction
C:To reduce temeprature
D:To reduce the speed of fast moving neutrons
Ans: D
10:The differential is located between propeller shaft and the
A:Clutch
B:Engine
C:Rear axle
D:None of the above
Ans: C
A:lime
B:Alumina
C:Iron Oxide
D:Alkalies
Ans: A
2:The most commonly used bond for all wall thickness is
A:Flemish bond
B:English bond
C:Stretching bond
D:Heading bond
Ans: B
3:A line normal to the plumb line at all points is known as
A:Horizontal line
B:Vertical line
C:Level line
D:Line of the collimation
Ans: C
4:In a wellconditioned triangle, no angle should be less than
A:30°
B:45°
C:60°
D:90°
Ans: A
5:A fixed point of reference of known elevation is called
A:Change point
B:Station point
C:Bench mark
D:Datum
Ans: C
6:The part which controls the air fuel ratio in a petrol engine is
A:Injector
B:Carburettor
C:Governor
D:None of the above
Ans: B
7:In IC Engines the process of removing burnt gases from combustion chamber of cylinder is known as
A:Supercharging
B:Polymerisation
C:Scavenging
D:Detonation
Ans: C
8:The compression ratio of Diesel engine varies from
A:15 to 25
B:10 to 15
C:6 to 10
D:25 to 40
Ans: A
9:The purpose of moderator in a nuclear power plant is
A:To moderate the radioactive pollution
B:To control reaction
C:To reduce temeprature
D:To reduce the speed of fast moving neutrons
Ans: D
10:The differential is located between propeller shaft and the
A:Clutch
B:Engine
C:Rear axle
D:None of the above
Ans: C
11:The minority carrier current in a semiconductor diode is largely a function of
A:Amount of doping
B:Temperature
C:Forward bias voltage
D:Reverse bias voltage
Ans: B
12:When the transistor is in high saturation, the biasing condition of base emitter BE and collector base CB junction is
A:BE forward biased, CE reverse biased
B:BE reversed biased, CE forward biased
C:BE forward biased, CE forward biased
D:BE reverse biased, CE reverse biased
Ans: C
13:Memory that losses its contents when power is lost is
A:Non volatile
B:Volatile
C:Flash memory
D:Static memory
Ans: B
14:In a bridge rectifier, if `V_m` is the peak voltage across the secondary of transformer, the maximum voltage coming across each reverse biased diode is
A:`V_m`/2
B:`V_m`/`sqrt(2)`
C:`2V_m`
D:`V_m`
Ans: D
15:The main advantage of CMOS is its
A:Low power consumption
B:High power rating
C:Small signal operation
D:Fast switching capability
Ans: A
16:The spacecharge region contains charges that are
A:Mostly majority carriers
B:Mostly minority carriers
C:Fixed donor and acceptor ions
D:Mobile donor and acceptor ions
Ans: C
17:The microwave tube that uses buncher and catcher cavities is
A:Magnetron
B:Klystron
C:Reflex Klystron
D:Travelling wave tube
Ans: B
18:Which of the following has same probability of error ?
A:BPSK and QAM
B:BPSK and ASK
C:BPSK and QPSK
D:BPSK and PAM
Ans: D
19:The negative resistance of the tunnel diode occurs when the bias voltage is
A:Between the peak and valley voltages
B:Above the valley voltage
C:Below the peak voltage
D:In the reverse direction
Ans: A
20:In an RC differentiator, the condition for differentiation is
A:RC >> 0.16T
B:RC << 0.16T
C:RC >> T/0.16
D:RC << T/0.16
Ans: B
21:For an input pulse train of clock period T, the delay produced by an n stage shift register is
A:2nT
B:nT
C:(n + 1)T
D:(n  1)T
Ans: C
22:An nchannel JFET has `I_(DSS)` = 1 mA and `V_(P)` = 5 V. Its maximum transconductance is
A:0.4 millimho
B:0.1 millimho
C:1.0 millimho
D:4.0 millimho
Ans: A
23:For thyristors, pulse triggering is preferred to dc triggering because
A:Gate dissipation is low
B:Pulse system is simpler
C:Triggering system is required for a very short duration
D:All of these
Ans: D
24:If an amplifier with a gain of −1000 and feedback of β=−0.1 had a gain change of 20% due to temperature, the change in gain of the feedback amplifier would be
A:0.2%
B:5%
C:10%
D:0.01%
Ans: A
25:The sensitivity of a multimeter is given in
A:Ω
B:KΩ/V
C:Amperes
D:V/KΩ
Ans: B
26:A superheterodyne radio receiver with an intermediate frequency of 455 KHz is tunded to a station operating at 1200 KHz. The associated image frequency is
A:55 KHz
B:1110 KHz
C:2110 KHz
D:4220 KHz
Ans: C
27:The multivibrator circuit configuration that can be used to convert a sinusoidal input into a square wave output is
A:A stable multivibrator
B:Monostable multivibrator
C:Bistable multivibrator
D:Schmitt trigger
Ans: D
28:A Yagi antenna in a horizontal plane produces
A:A broadside pattern
B:An endfire pattern
C:A figure of eight pattern
D:None of the above
Ans: B
29:A problem with class B push pull amplifier is that they usually suffer from
A:Harmonic distortion
B:Intermodulation distortion
C:Crossover distortion
D:None of these
Ans: C
30:A 12 bit binary number has an accuracy equivalent to the decimal fraction
A:1/1024
B:1/2048
C:1/6400
D:1/4096
Ans: D
31:If a pulse train with a frequency of 10 KHz is applied to the trigger input of a bistable multivibrator, the frequency of the output pulse train would be
A:5KHz
B:20 KHz
C:10 KHz
D:None of these
Ans: A
32:Six independent low pass signals of bandwith 3 W, W, W, 2W, 3W and 2W Hz are to be time division multiplexed on a common channel using PAM. To achieve this, the minimum transmission bandwidth of the channel should be __________ Hz.
A:12W
B:6W
C:3W
D:24 W
Ans: A
33:Class a amplifiers are characterised by
A:Maximum efficiency and minimum distortion
B:Minimum efficiency and maximum distortion
C:Maximum efficiency and maximum distortion
D:Minimum efficiency and minimum distortion
Ans: D
34:From cricuit design simplicity and economy point of view, one of the following configurations for a converter is the best. Which is that ?
A:Pushpull DCDC converter using one transformer
B:Ringing choke converter
C:Pushpull converter using two transformers
D:None of these
Ans: B
35:An opamp is having is having an open loop gain of `10^(5)` and open loop upper cutoff frequency of 10 Hz. If this opamp is connected as an amplifier with a closed loop gain at 100, then the new upper cutoff frequency will be
A:10 Hz
B:100 Hz
C:10 KHz
D:100 KHz
Ans: C
36:An amplifier power level is changed from 8 Watts to 16 Watts, equivalent dB gains is
A:2 dB
B:3dB
C:6 dB
D:5 dB
Ans: C
37:Which of the following statements are correct for the basic transistor amplifier configurations
A:CB amplifier has low input impedance and a low current gain
B:CC amplifier has low output impedance and a low current gain
C:CE amplifier has very poor voltage gain but very high input impedance
D:none of the above
Ans: A
38:In antenna measurement using two aperture antennas of dimensions D1 and D2, minimum speparation between the two should be (λ is free space wavelength of radiation uses)
A:(D1 + D2)/(2λ)
B:`(D1^2+D2^2)` /(λ)
C:(`D1^2+D2^2)` /(8λ)
D:`(D1^2+D2^2)` /2λ)
Ans: B
39:Compared to the junction transistor, FET
1) Has a larger gain banwidth product
2) Is less noisy
3) Has less input resistance
4) Has only the majority carrier flow
The correct statements are
A:1, 3
B:1, 2
C:3, 4
D:2, 4
Ans: D
40:How does 80386 change operation from real mode to protected mode ?
A:By resetting MSB of CR1 contents
B:By setting MSB of CR0 contents
C:By setting MSB of CR1 contents
D:By setting MSB of CR2 contents
Ans: B
41:A source follower (using a FET) usually has a voltage gain which is
A:Slightly less than unity, but positive
B:Greater than +1
C:Exactly unity but negative
D:About − 10
Ans: A
42:Which of the following logic family consumes the least amount of power ?
A:`I^2` L
B:ECL
C:TTL
D:CMOS
Ans: D
43:In a 100% amplitude modulated signal, the power in the lower sideband is : Assume carrier power to be 100 watts and modulation system to be SSBSC.
A:50 watts
B:100 watts
C:25 watts
D:None of these
Ans: C
44:A combinational logic circuit which is used to sen data coming from a source to two or more seperate
destinations is called as
A:Demultiplexer
B:Encoder
C:Multiplier
D:Decoder
Ans: A
45:The pinch off voltage of a JFET is 5V. Its cut off voltage is
A:`(5.0)^(1/2)`V
B:2.5 V
C:`(5.0)^(3/2)V`
D:5.0 V
Ans: D
46:A full wave rectifier uses two diodes, the internal resistance of each diode may be 20Ω each. The transformer rms secondary voltage from centre tap to each of secondary is 50V and load resistance is 980 Ω. Find the mean load current and rms value of load current.
A:0.05/`sqrt(2)` , 0.05`pi`
B:0.05`sqrt(2)` ``/`pi` , 0.05
C:0.1`sqrt(2)` ` ` /`pi` ,0.05
D:50`sqrt(2)`/`pi` , 50
Ans: C
47:The 2732 is a 4096 `xx` 8 EPROM. How many address lines does it have ?
A:8
B:12
C:1600
D:2732
Ans: B
48:Three equal resistors are connected in series across an emf source, dissipate 60 W of power. What is the power dissipated if the same resistors are connected in parallel ?
A:270
B:60
C:20
D:180
Ans: B
49:Most of the linear IC s are based on the two transistor differential amplifier because of its
A:High CMRR
B:High voltage gain
C:High input resistance
D:Input voltage dependent linear transfer characteristics
Ans: A
50:A speech signal occupying the bandwidth of 300 Hz to 3 KHz is converted into PCM format for use in digital communication. If the sampling frequency is 8 KHz and each sample quantized into 256 levels, then the output bit rate will be
A:3 Kb/s
B:8 Kb/s
C:256 Kb/s
D:64 Kb/s
Ans: D
51:A push pull inverter provides a
A:Highly regulated output
B:Constant DC output
C:Square wave output
D:None of these
Ans: C
52:When an antenna is placed in a vertical plane it will produce ?
A:Circularly polarised waves
B:Elliptically polarised waves
C:Horizontally polarised waves
D:Vertically polarised waves
Ans: C
53:The octal equivalent of decimal 324.781 is
A:40.987
B:540.781
C:215.234
D:504.771
Ans: D
54:In a travelling wave tube, the phase velocity of the axial components of the field of the slow wave structure is kept
A:Slightly less than the velocity of electrons
B:Equal to the velocity of the electrons
C:Slightly more than the velocity of electrons
D:Equal to the velocity of light in free space
Ans: B
55:Address bus of 8086 contains
A:20 lines
B:32 lines
C:16 lines
D:24 lines
Ans: A
56:The propagation delay for ECL IC family is approximately
A:2ns
B:10ns
C:25ns
D:50ns
Ans: A
57:The preemphasis circuit is used
A:After modulation
B:To increase or emphasise the amplitude low frequency
C:Prior to modulation
D:None of these
Ans: C
58:A NAND circuit with positive logic will operate as
A:AND with negative logic
B:AND with negative logic
C:OR with negative logic
D:NOR with negative logic
Ans: D
59:The average on state current for an SCR is 20A for a conduction angle of 120°. The average on=state current for 60° conduction angle will be
A:20 A
B:Less than 20 A
C:10 A
D:40 A
Ans: B
60:A switched mode power supply operating at 20 KHz to 100 KHz range uses _______ as the main switching element.
A:MOSFET
B:Triac
C:Thyristor
D:UJT
Ans: A
61:The biggest disadvantage of CW Doppler radar is that
A:It does not give the target position
B:It does not give target velocity
C:It does not give target range
D:A transponder is required at the target
Ans: C
62:The field frequency of HDTV is
A:15
B:60
C:30
D:120
Ans: B
63:An NPN transistor has a beta frequency `f_beta` of 1 MHz, and emitter short circuit low frequency current gain `beta_(0)` of 200. The unity gain frequency `f_(T)` and alpha cutoff frequency `f_(alpha)` respectively are
A:199 MHz, 200 MHz
B:200 MHz, 199 MHz
C:201 MHz, 200 MHz
D:200 MHz, 201 MHz
Ans: D
64:An opamp has a slew rate of 5V/μS. The largest sine wave output voltage possible at frequency of 1 MHZ is
A:10π volts
B:5 volts
C:(5/π)volts
D:(5/2π)volts
Ans: D
65:The number of comparisons carried out in a 5 bit flash type A/D converter is
A:31
B:32
C:5
D:3
Ans: A
66:A PLA can be used
A:As a dynamic memory
B:To realise a combinational logic
C:As a microprocessor
D:To realise a sequential logic
Ans: B
67:Hamming codes are used for error detection and correction. If the minimum hamming distance is m, then the number of errors correctable is
A:Equal to 2 m
B:Equal to m
C:Less than m/2
D:Greater than m
Ans: C
68:Given that `W=e^(i(2`Pi` /N)` , where N = 3. Then `F = W^N` can be computed as F =
A:0
B:1
C:e
D:−1
Ans: B
69:The code division multiple access technique is not used in satellite communication because of
A:Wastage of power
B:Wastage of baseband spectrum
C:Increase in delay
D:Complexity and unreliability of operation
Ans: A
70:Which of the following is introduced in the frequency sampling realization of the FIR filter ?
A:Poles are more in number on unit circle
B:Zeros are more in number on the unit circle
C:Poles and zeros at equally spaced points on the unit circle
D:None of the above
Ans: C
71:The number of LED display indicators in logic probes are
A:1
B:4
C:1 or 2
D:2
Ans: D
72:In a linear IC voltage, series pass transistor always operates in _________ region.
A:Active
B:Saturation
C:Cutoff
D:All of the above
Ans: A
73:The data rate of QPSK is ________ of BPSK.
A:Thirce
B:4 times
C:Twice
D:Same
Ans: C
74:Asymmetrical astable multivibrartor has R = 100Ω and C =0.1mF. The periodic time T is equal to
A:138 mS
B:69 mS
C:6.9 mS
D:13.8 mS
Ans: D
75:Bootstrap sweep circuit generally employs
A:CE amplifier
B:Emitter follower
C:CB amplifier
D:Tuned amplifier
Ans: B
76:If P=```[[1,0],[0,1]]` and Q=`[[0,1],[1,0]]` , then PQ is
A:A null matrix
B:An identity matrix
C:A singular matrix
D:A symmetric matrix
Ans: D
77:If P = `[[2,3],[5,7]]`, then `P^1` =
A:`[[2,3],[5,7]]`
B:`[[7,3],[5,2]]`
C:`[[7,3],[5,2]]`
D:`[[2,5],[3,7]]`
Ans: C
78:The first three terms in the expansion of `(a+bx)^m` are 1, 6x and 16`x^2` respectively (`alpha` > 0, m is a
natural number). Then
A:m = 9, b = `2/3`
B:m = 2, b = 3
C:m = 4, b = `3/2`
D:m = 3, b = 2
Ans: A
79:The value of cot 1°+ cot 89° is
A:0
B:1
C:`2/sin 2^o`
D:None of these
Ans: C
80:In Δ ABC, the value of is
A:−2 tan A sin B cos C
B:0
C:`tan^2` A
D:tan A(tan A−2 sin B cos C)
Ans: B
81:The xintercept of the line passing through the point (1, 1) and perpendicular to the line
x − 2y + 1 = 0 is
A:`2/3`
B:`(2)/(3)`
C:`3/2`
D:`(3)/(2)`
Ans: C
82:If , then the value of `lim_(x>0)``f(x)/x^2` is
A:–2
B:0
C:1
D:2
Ans: B
83:If x = a(cos `theta` −log cot `theta/2`) , y = a sin `theta`, then `dy/dx` =
A:tan θ
B:−tan `theta`
C:cot `theta`
D:−cot `theta`
Ans: A
84:The integral of ` `` `with respect to x is
A:`tan(xe^(x))/((x+1)e^(x))`+C
B:sec`(xe^(x))``tan(xe^(x))+C`
C:sec`(xe^(2))``+C`
D:`tan(xe^(x))+C`
Ans: D
85:The slope of normal to a curve at any point (x, y) on it is `(x)/((x+1)y)` . The equation of the curve is
A:y = `Cxe^x`
B:xy=`Ce^x`
C:xy=`Ce^x`
D:`y^(2)=2[log(x+1)x]+C`
Ans: A
86:The Coulomb is equal to charge on __________ electrons.
A:1.602` xx` `10^19`
B:6.28 `xx` `10^18`
C:1.67 `xx` `10^27`
D:6.18 `xx` `10^28`
Ans: B
87:The Ohm's laws deals with the relation between
A:Charge and capacity
B:Capacity and p.d.
C:Charge and resistance
D:Current and p.d.
Ans: D
88:One kwh is equal to __________ kCal.
A:860
B:735.5
C:36 `xx` `10^5`
D:746
Ans: A
89:Resistivity is usually expressed in terms of
A:ohm/°`^C`
B:Moh
C:Ohm meter
D:Ohm/cm square
Ans: C
A:Amount of doping
B:Temperature
C:Forward bias voltage
D:Reverse bias voltage
Ans: B
12:When the transistor is in high saturation, the biasing condition of base emitter BE and collector base CB junction is
A:BE forward biased, CE reverse biased
B:BE reversed biased, CE forward biased
C:BE forward biased, CE forward biased
D:BE reverse biased, CE reverse biased
Ans: C
13:Memory that losses its contents when power is lost is
A:Non volatile
B:Volatile
C:Flash memory
D:Static memory
Ans: B
14:In a bridge rectifier, if `V_m` is the peak voltage across the secondary of transformer, the maximum voltage coming across each reverse biased diode is
A:`V_m`/2
B:`V_m`/`sqrt(2)`
C:`2V_m`
D:`V_m`
Ans: D
15:The main advantage of CMOS is its
A:Low power consumption
B:High power rating
C:Small signal operation
D:Fast switching capability
Ans: A
16:The spacecharge region contains charges that are
A:Mostly majority carriers
B:Mostly minority carriers
C:Fixed donor and acceptor ions
D:Mobile donor and acceptor ions
Ans: C
17:The microwave tube that uses buncher and catcher cavities is
A:Magnetron
B:Klystron
C:Reflex Klystron
D:Travelling wave tube
Ans: B
18:Which of the following has same probability of error ?
A:BPSK and QAM
B:BPSK and ASK
C:BPSK and QPSK
D:BPSK and PAM
Ans: D
19:The negative resistance of the tunnel diode occurs when the bias voltage is
A:Between the peak and valley voltages
B:Above the valley voltage
C:Below the peak voltage
D:In the reverse direction
Ans: A
20:In an RC differentiator, the condition for differentiation is
A:RC >> 0.16T
B:RC << 0.16T
C:RC >> T/0.16
D:RC << T/0.16
Ans: B
21:For an input pulse train of clock period T, the delay produced by an n stage shift register is
A:2nT
B:nT
C:(n + 1)T
D:(n  1)T
Ans: C
22:An nchannel JFET has `I_(DSS)` = 1 mA and `V_(P)` = 5 V. Its maximum transconductance is
A:0.4 millimho
B:0.1 millimho
C:1.0 millimho
D:4.0 millimho
Ans: A
23:For thyristors, pulse triggering is preferred to dc triggering because
A:Gate dissipation is low
B:Pulse system is simpler
C:Triggering system is required for a very short duration
D:All of these
Ans: D
24:If an amplifier with a gain of −1000 and feedback of β=−0.1 had a gain change of 20% due to temperature, the change in gain of the feedback amplifier would be
A:0.2%
B:5%
C:10%
D:0.01%
Ans: A
25:The sensitivity of a multimeter is given in
A:Ω
B:KΩ/V
C:Amperes
D:V/KΩ
Ans: B
26:A superheterodyne radio receiver with an intermediate frequency of 455 KHz is tunded to a station operating at 1200 KHz. The associated image frequency is
A:55 KHz
B:1110 KHz
C:2110 KHz
D:4220 KHz
Ans: C
27:The multivibrator circuit configuration that can be used to convert a sinusoidal input into a square wave output is
A:A stable multivibrator
B:Monostable multivibrator
C:Bistable multivibrator
D:Schmitt trigger
Ans: D
28:A Yagi antenna in a horizontal plane produces
A:A broadside pattern
B:An endfire pattern
C:A figure of eight pattern
D:None of the above
Ans: B
29:A problem with class B push pull amplifier is that they usually suffer from
A:Harmonic distortion
B:Intermodulation distortion
C:Crossover distortion
D:None of these
Ans: C
30:A 12 bit binary number has an accuracy equivalent to the decimal fraction
A:1/1024
B:1/2048
C:1/6400
D:1/4096
Ans: D
31:If a pulse train with a frequency of 10 KHz is applied to the trigger input of a bistable multivibrator, the frequency of the output pulse train would be
A:5KHz
B:20 KHz
C:10 KHz
D:None of these
Ans: A
32:Six independent low pass signals of bandwith 3 W, W, W, 2W, 3W and 2W Hz are to be time division multiplexed on a common channel using PAM. To achieve this, the minimum transmission bandwidth of the channel should be __________ Hz.
A:12W
B:6W
C:3W
D:24 W
Ans: A
33:Class a amplifiers are characterised by
A:Maximum efficiency and minimum distortion
B:Minimum efficiency and maximum distortion
C:Maximum efficiency and maximum distortion
D:Minimum efficiency and minimum distortion
Ans: D
34:From cricuit design simplicity and economy point of view, one of the following configurations for a converter is the best. Which is that ?
A:Pushpull DCDC converter using one transformer
B:Ringing choke converter
C:Pushpull converter using two transformers
D:None of these
Ans: B
35:An opamp is having is having an open loop gain of `10^(5)` and open loop upper cutoff frequency of 10 Hz. If this opamp is connected as an amplifier with a closed loop gain at 100, then the new upper cutoff frequency will be
A:10 Hz
B:100 Hz
C:10 KHz
D:100 KHz
Ans: C
36:An amplifier power level is changed from 8 Watts to 16 Watts, equivalent dB gains is
A:2 dB
B:3dB
C:6 dB
D:5 dB
Ans: C
37:Which of the following statements are correct for the basic transistor amplifier configurations
A:CB amplifier has low input impedance and a low current gain
B:CC amplifier has low output impedance and a low current gain
C:CE amplifier has very poor voltage gain but very high input impedance
D:none of the above
Ans: A
38:In antenna measurement using two aperture antennas of dimensions D1 and D2, minimum speparation between the two should be (λ is free space wavelength of radiation uses)
A:(D1 + D2)/(2λ)
B:`(D1^2+D2^2)` /(λ)
C:(`D1^2+D2^2)` /(8λ)
D:`(D1^2+D2^2)` /2λ)
Ans: B
39:Compared to the junction transistor, FET
1) Has a larger gain banwidth product
2) Is less noisy
3) Has less input resistance
4) Has only the majority carrier flow
The correct statements are
A:1, 3
B:1, 2
C:3, 4
D:2, 4
Ans: D
40:How does 80386 change operation from real mode to protected mode ?
A:By resetting MSB of CR1 contents
B:By setting MSB of CR0 contents
C:By setting MSB of CR1 contents
D:By setting MSB of CR2 contents
Ans: B
41:A source follower (using a FET) usually has a voltage gain which is
A:Slightly less than unity, but positive
B:Greater than +1
C:Exactly unity but negative
D:About − 10
Ans: A
42:Which of the following logic family consumes the least amount of power ?
A:`I^2` L
B:ECL
C:TTL
D:CMOS
Ans: D
43:In a 100% amplitude modulated signal, the power in the lower sideband is : Assume carrier power to be 100 watts and modulation system to be SSBSC.
A:50 watts
B:100 watts
C:25 watts
D:None of these
Ans: C
44:A combinational logic circuit which is used to sen data coming from a source to two or more seperate
destinations is called as
A:Demultiplexer
B:Encoder
C:Multiplier
D:Decoder
Ans: A
45:The pinch off voltage of a JFET is 5V. Its cut off voltage is
A:`(5.0)^(1/2)`V
B:2.5 V
C:`(5.0)^(3/2)V`
D:5.0 V
Ans: D
46:A full wave rectifier uses two diodes, the internal resistance of each diode may be 20Ω each. The transformer rms secondary voltage from centre tap to each of secondary is 50V and load resistance is 980 Ω. Find the mean load current and rms value of load current.
A:0.05/`sqrt(2)` , 0.05`pi`
B:0.05`sqrt(2)` ``/`pi` , 0.05
C:0.1`sqrt(2)` ` ` /`pi` ,0.05
D:50`sqrt(2)`/`pi` , 50
Ans: C
47:The 2732 is a 4096 `xx` 8 EPROM. How many address lines does it have ?
A:8
B:12
C:1600
D:2732
Ans: B
48:Three equal resistors are connected in series across an emf source, dissipate 60 W of power. What is the power dissipated if the same resistors are connected in parallel ?
A:270
B:60
C:20
D:180
Ans: B
49:Most of the linear IC s are based on the two transistor differential amplifier because of its
A:High CMRR
B:High voltage gain
C:High input resistance
D:Input voltage dependent linear transfer characteristics
Ans: A
50:A speech signal occupying the bandwidth of 300 Hz to 3 KHz is converted into PCM format for use in digital communication. If the sampling frequency is 8 KHz and each sample quantized into 256 levels, then the output bit rate will be
A:3 Kb/s
B:8 Kb/s
C:256 Kb/s
D:64 Kb/s
Ans: D
51:A push pull inverter provides a
A:Highly regulated output
B:Constant DC output
C:Square wave output
D:None of these
Ans: C
52:When an antenna is placed in a vertical plane it will produce ?
A:Circularly polarised waves
B:Elliptically polarised waves
C:Horizontally polarised waves
D:Vertically polarised waves
Ans: C
53:The octal equivalent of decimal 324.781 is
A:40.987
B:540.781
C:215.234
D:504.771
Ans: D
54:In a travelling wave tube, the phase velocity of the axial components of the field of the slow wave structure is kept
A:Slightly less than the velocity of electrons
B:Equal to the velocity of the electrons
C:Slightly more than the velocity of electrons
D:Equal to the velocity of light in free space
Ans: B
55:Address bus of 8086 contains
A:20 lines
B:32 lines
C:16 lines
D:24 lines
Ans: A
56:The propagation delay for ECL IC family is approximately
A:2ns
B:10ns
C:25ns
D:50ns
Ans: A
57:The preemphasis circuit is used
A:After modulation
B:To increase or emphasise the amplitude low frequency
C:Prior to modulation
D:None of these
Ans: C
58:A NAND circuit with positive logic will operate as
A:AND with negative logic
B:AND with negative logic
C:OR with negative logic
D:NOR with negative logic
Ans: D
59:The average on state current for an SCR is 20A for a conduction angle of 120°. The average on=state current for 60° conduction angle will be
A:20 A
B:Less than 20 A
C:10 A
D:40 A
Ans: B
60:A switched mode power supply operating at 20 KHz to 100 KHz range uses _______ as the main switching element.
A:MOSFET
B:Triac
C:Thyristor
D:UJT
Ans: A
61:The biggest disadvantage of CW Doppler radar is that
A:It does not give the target position
B:It does not give target velocity
C:It does not give target range
D:A transponder is required at the target
Ans: C
62:The field frequency of HDTV is
A:15
B:60
C:30
D:120
Ans: B
63:An NPN transistor has a beta frequency `f_beta` of 1 MHz, and emitter short circuit low frequency current gain `beta_(0)` of 200. The unity gain frequency `f_(T)` and alpha cutoff frequency `f_(alpha)` respectively are
A:199 MHz, 200 MHz
B:200 MHz, 199 MHz
C:201 MHz, 200 MHz
D:200 MHz, 201 MHz
Ans: D
64:An opamp has a slew rate of 5V/μS. The largest sine wave output voltage possible at frequency of 1 MHZ is
A:10π volts
B:5 volts
C:(5/π)volts
D:(5/2π)volts
Ans: D
65:The number of comparisons carried out in a 5 bit flash type A/D converter is
A:31
B:32
C:5
D:3
Ans: A
66:A PLA can be used
A:As a dynamic memory
B:To realise a combinational logic
C:As a microprocessor
D:To realise a sequential logic
Ans: B
67:Hamming codes are used for error detection and correction. If the minimum hamming distance is m, then the number of errors correctable is
A:Equal to 2 m
B:Equal to m
C:Less than m/2
D:Greater than m
Ans: C
68:Given that `W=e^(i(2`Pi` /N)` , where N = 3. Then `F = W^N` can be computed as F =
A:0
B:1
C:e
D:−1
Ans: B
69:The code division multiple access technique is not used in satellite communication because of
A:Wastage of power
B:Wastage of baseband spectrum
C:Increase in delay
D:Complexity and unreliability of operation
Ans: A
70:Which of the following is introduced in the frequency sampling realization of the FIR filter ?
A:Poles are more in number on unit circle
B:Zeros are more in number on the unit circle
C:Poles and zeros at equally spaced points on the unit circle
D:None of the above
Ans: C
71:The number of LED display indicators in logic probes are
A:1
B:4
C:1 or 2
D:2
Ans: D
72:In a linear IC voltage, series pass transistor always operates in _________ region.
A:Active
B:Saturation
C:Cutoff
D:All of the above
Ans: A
73:The data rate of QPSK is ________ of BPSK.
A:Thirce
B:4 times
C:Twice
D:Same
Ans: C
74:Asymmetrical astable multivibrartor has R = 100Ω and C =0.1mF. The periodic time T is equal to
A:138 mS
B:69 mS
C:6.9 mS
D:13.8 mS
Ans: D
75:Bootstrap sweep circuit generally employs
A:CE amplifier
B:Emitter follower
C:CB amplifier
D:Tuned amplifier
Ans: B
76:If P=```[[1,0],[0,1]]` and Q=`[[0,1],[1,0]]` , then PQ is
A:A null matrix
B:An identity matrix
C:A singular matrix
D:A symmetric matrix
Ans: D
77:If P = `[[2,3],[5,7]]`, then `P^1` =
A:`[[2,3],[5,7]]`
B:`[[7,3],[5,2]]`
C:`[[7,3],[5,2]]`
D:`[[2,5],[3,7]]`
Ans: C
78:The first three terms in the expansion of `(a+bx)^m` are 1, 6x and 16`x^2` respectively (`alpha` > 0, m is a
natural number). Then
A:m = 9, b = `2/3`
B:m = 2, b = 3
C:m = 4, b = `3/2`
D:m = 3, b = 2
Ans: A
79:The value of cot 1°+ cot 89° is
A:0
B:1
C:`2/sin 2^o`
D:None of these
Ans: C
80:In Δ ABC, the value of is
A:−2 tan A sin B cos C
B:0
C:`tan^2` A
D:tan A(tan A−2 sin B cos C)
Ans: B
81:The xintercept of the line passing through the point (1, 1) and perpendicular to the line
x − 2y + 1 = 0 is
A:`2/3`
B:`(2)/(3)`
C:`3/2`
D:`(3)/(2)`
Ans: C
82:If , then the value of `lim_(x>0)``f(x)/x^2` is
A:–2
B:0
C:1
D:2
Ans: B
83:If x = a(cos `theta` −log cot `theta/2`) , y = a sin `theta`, then `dy/dx` =
A:tan θ
B:−tan `theta`
C:cot `theta`
D:−cot `theta`
Ans: A
84:The integral of ` `` `with respect to x is
A:`tan(xe^(x))/((x+1)e^(x))`+C
B:sec`(xe^(x))``tan(xe^(x))+C`
C:sec`(xe^(2))``+C`
D:`tan(xe^(x))+C`
Ans: D
85:The slope of normal to a curve at any point (x, y) on it is `(x)/((x+1)y)` . The equation of the curve is
A:y = `Cxe^x`
B:xy=`Ce^x`
C:xy=`Ce^x`
D:`y^(2)=2[log(x+1)x]+C`
Ans: A
86:The Coulomb is equal to charge on __________ electrons.
A:1.602` xx` `10^19`
B:6.28 `xx` `10^18`
C:1.67 `xx` `10^27`
D:6.18 `xx` `10^28`
Ans: B
87:The Ohm's laws deals with the relation between
A:Charge and capacity
B:Capacity and p.d.
C:Charge and resistance
D:Current and p.d.
Ans: D
88:One kwh is equal to __________ kCal.
A:860
B:735.5
C:36 `xx` `10^5`
D:746
Ans: A
89:Resistivity is usually expressed in terms of
A:ohm/°`^C`
B:Moh
C:Ohm meter
D:Ohm/cm square
Ans: C
90. A resistor with colour coded value of 1000 ohms and ± 20% tolerance can have an actual resistance between (
A) 980 Ohm and 1020 Ohm
(B) 800 Ohm and 1000 Ohm
(C) 1000 Ohm and 1200 Ohm
(D) 800 Ohm and 1200 Ohm
Ans: D
91. For a carboncomposition resistor colour coded with Yellow, Violet, Orange and Silver stripes left to right, the resistance and tolerance are
(A) 470 Ohms ± 5% (B) 47 Kilo Ohm ± 10% (C) 47 Mega Ohms ± 5% (D) 4700 Ohms ± 10%
Ans: B
92. Five Capacitors each of 5 µF are connected in parallel, the equivalent capacitance will be
(A) 25 µF (B) 15 µF
(C) 1 µF (D) 10 µF
Ans: A
93. The resistance of a conductor of diameter D and length L is R Ω. If the diameter of the conductor is halved and its length is doubled, the resistance will be
(A) R Ω (B) 2R Ω
(C) 4R Ω (D) 8R Ω
Ans: D
94. The electrical energy consumed by a coil is stored in the form of :
(A) An electrical field (B) A force field (C) An electrostatic field (D) A magnetic field
Ans: D
95. In a purely inductive circuit
(A) Current leads voltage by 90° (B) Voltage lags current by 90°
(C) Voltage leads current by 90° (D) Voltage and Current are in Phase (0°)
Ans: C
96. A semiconductor has ______ Valence Electrons.
(A) 5 (B) 6 (C) 4 (D) 3
Ans: C
97. The strength of a semiconductor crystal comes from ______.
(A) Forces between Protons (B) Forces between Nuclei (
C) ElectronPair Bonds (D) None of the above
Ans: C
98. If Doping level of a crystal diode is increased, the breakdown voltage ______.
(A) is increased (B) is decreased
(C) remains the same (D) None of the above
Ans: B
99. A Zener diode has ______.
(A) One PN Junction (B) Two PN Junction
(C) Three PN Junction (D) Four PN Junction
Ans: A
100. Fermi level for extrinsic semiconductor depends on
(A) Donor Element (B) Impurity Concentration
(C) Temperature (D) All of the above
Ans: D
A) 980 Ohm and 1020 Ohm
(B) 800 Ohm and 1000 Ohm
(C) 1000 Ohm and 1200 Ohm
(D) 800 Ohm and 1200 Ohm
Ans: D
91. For a carboncomposition resistor colour coded with Yellow, Violet, Orange and Silver stripes left to right, the resistance and tolerance are
(A) 470 Ohms ± 5% (B) 47 Kilo Ohm ± 10% (C) 47 Mega Ohms ± 5% (D) 4700 Ohms ± 10%
Ans: B
92. Five Capacitors each of 5 µF are connected in parallel, the equivalent capacitance will be
(A) 25 µF (B) 15 µF
(C) 1 µF (D) 10 µF
Ans: A
93. The resistance of a conductor of diameter D and length L is R Ω. If the diameter of the conductor is halved and its length is doubled, the resistance will be
(A) R Ω (B) 2R Ω
(C) 4R Ω (D) 8R Ω
Ans: D
94. The electrical energy consumed by a coil is stored in the form of :
(A) An electrical field (B) A force field (C) An electrostatic field (D) A magnetic field
Ans: D
95. In a purely inductive circuit
(A) Current leads voltage by 90° (B) Voltage lags current by 90°
(C) Voltage leads current by 90° (D) Voltage and Current are in Phase (0°)
Ans: C
96. A semiconductor has ______ Valence Electrons.
(A) 5 (B) 6 (C) 4 (D) 3
Ans: C
97. The strength of a semiconductor crystal comes from ______.
(A) Forces between Protons (B) Forces between Nuclei (
C) ElectronPair Bonds (D) None of the above
Ans: C
98. If Doping level of a crystal diode is increased, the breakdown voltage ______.
(A) is increased (B) is decreased
(C) remains the same (D) None of the above
Ans: B
99. A Zener diode has ______.
(A) One PN Junction (B) Two PN Junction
(C) Three PN Junction (D) Four PN Junction
Ans: A
100. Fermi level for extrinsic semiconductor depends on
(A) Donor Element (B) Impurity Concentration
(C) Temperature (D) All of the above
Ans: D