Exam : Electronics and Communication Engineering

Q1: Standard deviation of first 15 even natural numbers is

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q2:

⚪ a) 0

⚪ b) -i / 108 ⚪ c) i / 108

⚪ d) 2i / 108

Q3:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q4:

⚪ a) Cot 2x

⚪ b) Tan 2x ⚪ c) Cos 2x ⚪ d) Sin 2x

Q5:

⚪ a) 1/2

⚪ b) 1/3 ⚪ c) 1/4 ⚪ d) 1/5

Q6:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q7:

⚪ a) 0

⚪ b) 1 ⚪ c) 2 ⚪ d) 3

Q8:

⚪ a) 2

⚪ b) 3 ⚪ c) 4 ⚪ d) 5

Q9:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q10:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q11: Ideal current sources have:

⚪ a) Zero internal resistance ⚪ b) Low voltage

⚪ c) Infinite internal resistance ⚪ d) Large current

Q12: If there are three branches and two nodes, the number of links present in co-tree are:

⚪ a) 4 ⚪ b) 2 ⚪ c) 8 ⚪ d) 6

Q13: While considering a source in superposition theorem, all other voltage sources are:

⚪ a) Open circuited ⚪ b) Removed

⚪ c) Short circuited ⚪ d) Changed from their original position

Q14:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q15: If an impedance ZL is connected across a voltage source V with source impedance ZS then for maximum powertransfer, the load impedance must be equal to:

⚪ a) Source impedance ZS

⚪ b) Complex conjugate of ZS ⚪ c) Real part of ZS

⚪ d) Imaginary part of ZS

Q16: Under steady state condition, ______ behaves as a short circuit and _______ as an open circuit.

⚪ a) Resistor, capacitor ⚪ b) Capacitor, inductor ⚪ c) Capacitor, resistor

⚪ d) Inductor, capacitor

Q17:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q18: The loop method of circuit analysis is based on:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q19:

⚪ a) 6V

⚪ b) 25 V ⚪ c) 10 V ⚪ d) 40 V

Q20: If a network consists of only independent current sources and resistors and the values of all the current sources aredoubled, then values of node voltages:

⚪ a) Remain same

⚪ b) Will be doubled ⚪ c) Will be halved

⚪ d) Will be four times

Q21: A two-port network is reciprocal if and only if:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q22:

⚪ a) Open circuit

⚪ b) Short circuit ⚪ c) Voltage source

⚪ d) Current source

Q23:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q24:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q25:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q26:

⚪ a) Causal, Linear and time invariant

⚪ b) Non - Causal, Linear and time variant ⚪ c) Causal, Linear and time variant

⚪ d) Non - Causal, Linear and time invariant

Q27:

⚪ a) x(t- 14)

⚪ b) x(t-4) ⚪ c) x(t+4)

⚪ d) x(t+14)

Q28:

⚪ a) Only if the value of an impulse response is zero for all negative values of time

⚪ b) Only if the value of an impulse response is unity for all negative values of time ⚪ c) Only if the value of an impulse response is infinity for all negative values of time

⚪ d) Only if the value of an impulse response is negative for all negative values of time

Q29:

⚪ a) 600 Hz

⚪ b) 150 Hz ⚪ c) 200 Hz ⚪ d) 300 Hz

Q30:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q31: Which of the following operation is not associated with discrete linear convolution?

⚪ a) Folding operation ⚪ b) Multification operation

⚪ c) Shifting operation ⚪ d) Integration operation

Q32: In a sinusoidal oscillator, sustained oscillations will be produced only if the loop gain ( at the oscillation frequency) is

⚪ a) Less than unity but not zero ⚪ b) Zero

⚪ c) Unity ⚪ d) Greater than unity

Q33:

⚪ a) 0.623

⚪ b) 0.678 ⚪ c) 0.693 ⚪ d) 0.625

Q34: Thermal runaway occurs when

⚪ a) Collector is reverse biased ⚪ b) Transistor is not biased

⚪ c) Emitter is forward biased ⚪ d) Junction capacitance is high

Q35: The field-effect transistor can be used as a variable

⚪ a) Capacitance ⚪ b) Reactance

⚪ c) Resistance ⚪ d) Inductance

Q36: Which of the following is second condition for oscillations?

⚪ a) A gain of one around the feedback loop ⚪ b) No gain around the feedback loop

⚪ c) The attention of the feedback circuit must be one third ⚪ d) The feedback circuit must be capacitive

Q37: Most common used semiconductor is ⚪ a) Germanium

⚪ b) Graphite ⚪ c) Tellurium ⚪ d) Silicon

Q38: MOSFET can be used as

⚪ a) Current controlled capacitor ⚪ b) Current controlled inductor

⚪ c) Voltage controlled capacitor ⚪ d) Voltage controlled inductor

Q39: The amount of energy that . . . . . is called Fermi level

⚪ a) A hole can have at room temperature ⚪ b) An electron can have at room temperature

⚪ c) A hole cannot have at room temperature ⚪ d) Must be given to an electron to move to the conduction band

Q40: . . . . . . . have the least forbidden energy gap between the valence and conduction band

⚪ a) Insulators ⚪ b) Metals

⚪ c) Semiconductors ⚪ d) Non Metals

Q41:

⚪ a) 375 mA

⚪ b) 37.5 mA ⚪ c) 3.75 mA ⚪ d) 0.375 mA

Q42: Which one of the following is not LED material?

⚪ a) GaAs ⚪ b) GaP

⚪ c) GaAsP ⚪ d) SiO2

Q43: A zener diode when biased correctly

⚪ a) Acts as a fixed resistance ⚪ b) Never overheats

⚪ c) Has a constant current passing through it ⚪ d) Has a constant voltage across it

Q44:

⚪ a) 5 - 12 mV

⚪ b) 1.7 - 3.3 V ⚪ c) 5 - 12 V

⚪ d) 20 - 25 V

Q45: Choose the correct statement

⚪ a) MOSFET is a unipolar, voltage controlled, two terminal device ⚪ b) MOSFET is a bipolar, current controlled, three terminal device ⚪ c) MOSFET is a unipolar, voltage controlled, three terminal device

⚪ d) MOSFET is a bipolar, current controlled, two terminal device

Q46: Which of the following cannot be fabricated on an IC?

⚪ a) Transistors ⚪ b) Diodes

⚪ c) Resistors ⚪ d) Large inductors and transformers

Q47: What is the SI unit of electron diffusion constant?

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q48: The cause of early effect in a bipolar junction transistor is

⚪ a) Fast turn-on ⚪ b) Large collector-base reverse bias

⚪ c) Fast turn-off ⚪ d) Large emitter-base forward bias

Q49: In the case of zener diode knee current implies . . . . . .

⚪ a) Forward bias current beyond which V-I characteristics is a straight line ⚪ b) Forward cut-in current beyond which current is directly proportional to voltage

⚪ c) Reverse bias current above which V-I characteristics is a straight line ⚪ d) Maximum allowable reverse bias current through a zener diode

Q50: In a reverse bias P-N junction diode, the magnitude of electric field is maximum at

⚪ a) The edge of depletion region on the P - side ⚪ b) The edge of depletion region on the N - side ⚪ c) At the P-N junction

⚪ d) The centre of the depletion region on the N - side

Q51:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q52: The output of a differentiating circuit is . . . . . . . . if the input is a saw tooth wave

⚪ a) Square ⚪ b) Triangular

⚪ c) Sine ⚪ d) Rectangular

Q53: The voltage regulation of an ideal regulated power supply is

⚪ a) 0% ⚪ b) 3% ⚪ c) 1% ⚪ d) 7%

Q54: If the oscillation amplitude decreases continuously, it is known as

⚪ a) Over-damped ⚪ b) Sustained

⚪ c) Undamped ⚪ d) Under-damped

Q55: In a BJT, if the collector-base junction and the base-emitter junction are both reverse-biased, which region is the BJToperating in?

⚪ a) Saturation region

⚪ b) Active region ⚪ c) Cut-off region ⚪ d) Depletion region

Q56: The 555 timer consists of . . . . . . . , a voltage divider, R-S flip-flop, buffer amplifier, a transistor switch, and an outputstage.

⚪ a) Two comparators

⚪ b) A comparator ⚪ c) A voltage amplifier

⚪ d) A peak detector

Q57: What are the characteristics of an ideal Op - Amp?

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q58: Which of the following circuit is equivalent to half-wave rectifier

⚪ a) A clamper circuit ⚪ b) A clamper circuit with negative bias

⚪ c) A clamper circuit with positive bias ⚪ d) A clipper circuit

Q59: . . . . . . . coupling provides the maximum voltage gain

⚪ a) RC ⚪ b) Transformer

⚪ c) Direct ⚪ d) Impedance

Q60: What are the important characteristics of CMOS devices?

⚪ a) Power Dissipation ⚪ b) Low static power consumption

⚪ c) High resistivity ⚪ d) Both high noise immunity and low static power consumption

Q61: The pull-up resistor is required while connecting TTL logic to CMOS logic in order to:

⚪ a) Decrease output high voltage ⚪ b) Increase output low voltage

⚪ c) Decrease output low voltage ⚪ d) Increase output high voltage

Q62: The cycle used to fetch and execute an instruction in 8085 microprocessor is known as:

⚪ a) Machine cycle ⚪ b) Instruction cycle

⚪ c) Clock cycle ⚪ d) Memory cycle

Q63: Eight bits can be serially entered into the shift register in __________________, if it has clock frequency of 400 kHz.

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q64:

⚪ a) Greater than 3.846 MHz

⚪ b) Equal to 3.846 MHz ⚪ c) Equal to 4.167 MHz ⚪ d) Greater than 4.167 MHz

Q65: Number of 2:1 MUX required to design 64:1 MUX are:

⚪ a) 62 ⚪ b) 63 ⚪ c) 64 ⚪ d) 65

Q66: J-K flip flop toggles when:

⚪ a) J=1, K=1 ⚪ b) J=0, K=0 ⚪ c) J=0, K=1 ⚪ d) J=1, K=0

Q67: NAND gates are preferably used because they:

⚪ a) Consume less electronic power ⚪ b) Provide maximum density on chip

⚪ c) Can be used to make any gate ⚪ d) Have low fabrication area

Q68: The disadvantage of MOS capacitor in DRAM is:

⚪ a) It can not hold charge till long period ⚪ b) It is highly dense

⚪ c) It can store the data for long period ⚪ d) It is not flexible

Q69: How many T-states are required for the execution of CMA instruction in 8085?

⚪ a) 7 ⚪ b) 10

⚪ c) 4 ⚪ d) 13

Q70: In excess-3 code, if the addition of two numbers is less than 9, the correct answer is obtained by:

⚪ a) subtract 0110 from the sum ⚪ b) subtract 0011 from the sum ⚪ c) add 0011 to sum

⚪ d) add 0110 to sum

Q71: For a three-input XOR gate, how many possibilities will result in a HIGH output?

⚪ a) 2 ⚪ b) 6 ⚪ c) 8 ⚪ d) 4

Q72: How many 3-to-8 line decoders with an enable input are needed to construct a 6-to-64 line decoder without using anyother logic gate?

⚪ a) 10

⚪ b) 9 ⚪ c) 8 ⚪ d) 7

Q73:

⚪ a) 7

⚪ b) 6 ⚪ c) 5 ⚪ d) 4

Q74: Which is the fastest logic family?

⚪ a) DTL ⚪ b) TTL

⚪ c) MOS ⚪ d) ECL

Q75: Boolean algebra performs the task of:

⚪ a) Simplifying algebraic expressions ⚪ b) Maximizing the number of switches in circuits

⚪ c) Performing arithmetic calculations ⚪ d) Solving the mathematical problems

Q76:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q77:

⚪ a) Three

⚪ b) Two ⚪ c) One ⚪ d) Zero

Q78:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q79: The problem of instability exists in the control systems despite the presence of negative feedback because:

⚪ a) Components used have non-linearity ⚪ b) Approximations are involved in the mathematical analysis

⚪ c) Dynamic equations of the subsystems are not known exactly ⚪ d) System has a large negative phase angle at high frequencies

Q80:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q81: The system will be ______ if poles of the system lie on the imaginary axis in s-plane.

⚪ a) Stable ⚪ b) Conditionally Stable

⚪ c) Unstable ⚪ d) Marginally Stable

Q82: If there are no roots in the right half of s-plane but one or more pairs of simple roots are located on the imaginary axis ofthe s-plane, then the response due to initial condition:

⚪ a) Decrease to zero as the time approaches infinity

⚪ b) Is undamped sinusoidal oscillations ⚪ c) Increase as the time approaches infinity

⚪ d) Damped non-sinusoidal oscillation and the damping factor will depend upon the relative location of the roots on theimaginary axis

Q83: How many poles or zeros are present at the origin if starting slope is -40 dB/decade?

⚪ a) 2 poles ⚪ b) 1 pole

⚪ c) 1 zero ⚪ d) no pole

Q84: Which of the following is correct for phase lag compensation?

⚪ a) It increases bandwidth. ⚪ b) It improves relative stability.

⚪ c) It increases the speed of response. ⚪ d) It increases overshoot.

Q85:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q86: The product of ____________ gains while going through a forward path is known as path gain.

⚪ a) Branch ⚪ b) Loop

⚪ c) Path ⚪ d) Node

Q87:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q88:

⚪ a) -2

⚪ b) 2 ⚪ c) -1 ⚪ d) zero

Q89:

⚪ a) zero

⚪ b) One, anti-clockwise ⚪ c) Two, clockwise

⚪ d) One, clockwise

Q90: What will be the relation between the numerator (N) and denominator degree (M) of the transfer function if transferfunction has two zeros at infinity?

⚪ a) N = M + 1

⚪ b) N = M - 1 ⚪ c) N = M + 2 ⚪ d) N = M - 2

Q91: PCM values encoded by DPCM on the basis of

⚪ a) Quantization level ⚪ b) Difference between the current and predicted value

⚪ c) Interval between levels ⚪ d) Step size

Q92: Quantization level in PCM encoding, varies as a function of

⚪ a) Frequency ⚪ b) Square of frequency

⚪ c) Square of amplitude ⚪ d) Amplitude

Q93: In case of periodic signal the autocorrelation function equals to

⚪ a) Energy of the signal ⚪ b) Its area in frequency domain

⚪ c) Power of the signal ⚪ d) Its area in time domain

Q94: In an amplitude modulation system, if the total power is 600 W and the power in carrier is 400 W, then the modulationindex is

⚪ a) 0.5

⚪ b) 0.75 ⚪ c) 0.9

⚪ d) 1.0

Q95: Matched filter is a . . . . . . . . technique

⚪ a) Modulation

⚪ b) Demodulation ⚪ c) Modulation and Demodulation

⚪ d) Neither Modulation nor Demodulation

Q96: The bandwidth of an ASK modulated signal is:

⚪ a) Same as the bandwidth of baseband signal ⚪ b) Half the bandwidth of baseband signal

⚪ c) Double the bandwidth of baseband signal ⚪ d) Triple the bandwidth of baseband signal

Q97: Which of the following occupies maximum bandwidth

⚪ a) ASK ⚪ b) BPSK

⚪ c) FSK ⚪ d) DBPSK

Q98: Which stage of super heterodyne principle provides selectivity?

⚪ a) RF stage ⚪ b) IF stage

⚪ c) Demodulating Stage ⚪ d) Audio Stage

Q99: Entropy is the measure of . . . . . . .

⚪ a) Randomness ⚪ b) Information

⚪ c) Non-Randomness ⚪ d) Randomness and Information

Q100:

⚪ a) 10 W

⚪ b) 18 W ⚪ c) 20 W ⚪ d) 28 W

Q101: Granular noise occurs when

⚪ a) Step size is too small ⚪ b) There is interference from the adjacent channel

⚪ c) Step size is too large ⚪ d) Bandwidth is too large

Q102: Which of the following can be used to remove ISI?

⚪ a) Differential coding ⚪ b) Manchester coding ⚪ c) Polar NRZ

⚪ d) Non Polar NRZ

Q103: What is the capacity of Gaussian channel?

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q104: The parity bit for 1001011 is . . . . . .

⚪ a) 1 ⚪ b) 2 ⚪ c) 3 ⚪ d) 0

Q105: What is the CRC in cyclic redundancy checking?

⚪ a) The remainder ⚪ b) The quotient

⚪ c) The dividend ⚪ d) The divisor

Q106: The maximum value is achieved for transmission of power to a load over the transmission line when the standing waveratio is:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q107:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q108:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q109: The cut-off frequency of rectangular waveguide with dimensions 1 cm x 0.5 cm is:

⚪ a) 20 GHz ⚪ b) 15 GHz ⚪ c) 10 GHz ⚪ d) 5 GHz

Q110: A transmission line is distortion less if:

⚪ a) RL=1/GC ⚪ b) RL = GC ⚪ c) LG = RC ⚪ d) RG = LC

Q111: If antenna is having highly directive radiation pattern while transmitting, then radiation pattern while receiving :

⚪ a) Exhibits no directivity ⚪ b) Is more directive

⚪ c) Is same ⚪ d) Is less directive

Q112:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q113:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q114:

⚪ a) 100

⚪ b) 10 ⚪ c) 0.001

⚪ d) 0.01

Q115: When VSWR is 3, the magnitude of the reflection coefficient will be

⚪ a) 1/4 ⚪ b) 1/2 ⚪ c) 1/3 ⚪ d) 1

Q116: In impedance Smith Chart, movement along a constant resistance circle in clockwise direction leads to:

⚪ a) Decrease in the reactance value ⚪ b) No change in the reactance value

⚪ c) Increase in the reactance value ⚪ d) No change in the impedance

Q117:

⚪ a)

⚪ b)

⚪ c)

⚪ d)

Q118: A quarter wave impedance transformer is terminated by a short circuit. What would its input impedance be equal to?

⚪ a) Line characteristic impedance ⚪ b) Zero

⚪ c) Infinity ⚪ d) Square root of line characteristic impedance

Q119: The product of group velocity and phase velocity is equal to:

⚪ a) Speed of light ⚪ b) Half of the speed of light

⚪ c) One-fourth of the speed of light ⚪ d) Square of the speed of light

Q120: When a particular mode is excited on a waveguide, there appears an extra electric component in the direction ofpropagation. In what mode is the wave propagating?

⚪ a) Traverse electric

⚪ b) Traverse magnetic ⚪ c) Traverse electro-magnetic

⚪ d) Longitudinal