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# (Paper) MPPSC: Online Examination of State Engineering Service (Pre.) Exam - 2014 Second Paper (Electrical Engineering)

## Electrical Engineering

Q1 : The unit step sequence u[n] and impulse response [n] are related as -

Q2 : The system given as y(t)=x(t-8) is invertible then inverse system will be as

A y(t+8)
B y(t-8)
C y(2t+8)
D y(t-2)

Q3 :

A F(s)
B sF(s)–f(0)
C s2F(s)
D s3F(s)- f(0)

Q5 : The discrete-time system denoted by y[n]=x[n3] is

A Linear, time-varying and causal system
B Nonlinear, time-varying and causal system
C Linear, time-invariant and non-causal system
D Linear, time-variant and non-causal system

Q6 : If the voltage gain |V0/Vi| of an amplifier is 1/ , its value in dB is -

A +10 dB
B -6.93 dB
C -3 dB
D +3 dB

Q7 : The trigonometric Fourier series representation of an even signal does not have the following type of functions

B Cosine functions
C Sine functions
D Odd harmonic functions

Q8 : The impulse response of a linear time invariant system is given by h(t) = (t-2) + (t-3). The step response of this system at t=1 will be -

A 0
B 1
C 2
D 3

Q9 : The power spectral density and the autocorrelation function of an periodic signal are related by -

A The Fourier transformation
B The Laplace transformationC Both are same
D None of these is correct

Q10 : The power of a sinusoid signal x(t) = A/2 Cos(t) is given by -

A A2/4
B A2/2
C A2
D A2/8

Q11 : Assume that F1 and F2 denote the lower and upper half power frequencies of a series RLC circuit respectively and F0 denotes the resonance frequency. The selectivity of this RLC circuit is given by

Q12 : If eight resistors of 8 Ohm resistance of each are connected in parallel then the net resistance will be:

A 1
B 64
C 4
D 8

Q13 :

A 0,0
B 0,2
C 5,0
D 0,5

Q14 : The plot of the signal x(t) in the below figure represents:

A Energy signal
B Power signal
C Energy signal and Power signal
D None of these is correct

Q15 : Following is the magnitude of the impedance of the series RLC circuit running at angular frequency :

Q16 : In the given circuit in the below Figure, the value of V will be as follows:

A 80
B 70
C 20
D 10

Q17 : The superposition principle can not be applied for:

A voltage computation
B current computation
C power computation
D bilateral components

Q18 : If unit step current is applied to an initially relaxed capacitor, then the voltage across the capacitor will be- A Unit step function

B Ramp function
C Impulse function
D None of these is correct

Q19 : The mathematical expression for the velocity for travelling electromagnetic wave in free-space can be given as:

Q20 : The energy density corresponding to static magnetic field is as

Q21 : The SI unit of electrostatic field strength is

A volt-meter
B volt2
/meter
C volt/meter
D volt/meter2

Q22 : The equation is

A Maxwell’s equation
B Laplace’s equation
C Fourier equation
D Poisson’s equation

Q23 : Poynting vector represents:

A power density vector which produces electrostatic field
B current density vector which produces electrostatic field
C current density vector which produces electromagnetic field
D power density vector which produces electromagnetic field

Q24  The distance between adjacent maxima and minima in a standing wave of a transmission line is given by

/4
B /2
C /8
D

Q25 : The intrinsic impedance of free space is given by:

A 20 Ohm
B 277 Ohm
C 177 Ohm
D 377 Ohm

Q26 : The divergence of electric flux density at origin is

A 2
B 4
C -2
D 0

Q27 : The input signal for the A.C. bridges is applied from

A Oscillator system
B Amplifier system
C Regulated power supply system
D D.C. battery system

Q28 : The internal resistance of the ammeter should be very low so that

A It will have high sensitivity
B It will provide high accuracy
C It will provide maximum voltage drop across the meter
D It will provide minimum effect of the current in the circuit

Q29 : The Wien bridge can be used for the following

A Measurement of resistance
B Measurement of frequency
C Measurement of harmonic distortion
D Measurement of frequency and harmonic distortion

Q30 : The application of thermocouple transducer is

A Measurement of temperature B Measurement of velocity and vibration
C Measurement of pressure
D Measurement of gas flow

Q31 : A varactor can be defined as

A A diode which is used for variable capacitor
B A diode which is used for high speed switching
C A diode which is used for variable inductor
D A diode which is used for variable resistor

Q32 : Measurement of dielectric loss of capacitor can be performed by

A Using Wein bridge
B Using Owen bridge
C Using Schering bridge
D Using Maxwell bridge

Q33 : Siemens can be used as a unit for

A Measurement of conductance
B Measurement of resistance
C Measurement of flux density
D Measurement of electric field

Q34 : A cathode ray oscilloscope works based on the following -

A Electrostatic based focusing technique
B Electromagnetic based focusing technique
C Electrostatic and Electromagnetic based focusing technique
D None of these is correct

Q35 : Regenerative feedback means the following

A Feedback with step input
B Feedback with oscillations
C Feedback with positive sign
D Feedback with negative sign

Q36 : Laplace transform is not useful for analysis of the following control systems

A Linear systems
B Discrete- time systems
C Time- invariant systems
D Unstable continuous –time systems

Q37 : The transfer function of the following state model of an LTI system with zero initial condition is

Q38 : The time period of a square ware of frequency 1kHz is

A1 s
B 10 s
C 10-3 s
D 0.1 s

Q39 : If the state space representation of an LTI system is known then the transfer function of this system

A Can be partially determined
B Can be completely determined
C Cannot be completely determined
D None of these is correct

Q40 : What number of nybbles can make one byte

A1
B 2
C 4
D 8

Q41 : In a microprocessor, the data bus has 16 lines and address bus has 12 lines. What will be the number of bytes in the memory

A 4k
B 2k
C 8k
D 24k

Q42 : In Intel 8085 microprocessor, the address bus is 16 bit wide. The memory which can be accessed by this address bus will be

A 64 k bytes
B 2 k bytes
C 8 k bytes
D 12 k bytes

Q43 : The following memory is a permanent memory

A ROM
B RAM
C ROM AND RAM
D None of these is correct

Q44 : The assumption of ergodic process in communication system means -

A The random signals have identical time averages
B The random signals have identical ensemble averages
C The random signals have the identical time and ensemble averages
D None of these is correct

Q45 : The power spectral density of the stationary noise whose autocorrelation is R( )=e-3 | | , will be

Q46 : Entropy commonly measures :\

A The average informtion
B The rate of information
C The probability of information
D The loss of information

Q47 : The autocorrelation function of a signal at zero -lag will be :

A Mean value of signal
B Average power of signal
C Average voltage of signal
D Zero

Q48 : In DSB-SC system, at the receiver the detection process is expensive because :

A It requires synchronous detection
B Generation of local carrier is difficult at the receiver
C Power level of received signal is very low
D All options are correct

Q49 : In a PCM system, the signal to quantization error ratio for 8-bit words will be :

A 54 dB
B 30 dB
C 40 dB
D 64 dB

Q50 : Companding operation is useful because :

A It overcomes quantization noise in PCM
B It protects small signals in PCM from quantizing noise
C It reduces impulse noise in PWM receivers
D None of these is correct

Q51 : Which of the following pulse modulation technique is analog:

A Differential PCM
B PCM
C PWM
D Delta

Q52 : Frequency shift keying can be considered as a method for introducing:

A Frequency modulation
B Amplitude modulation
C Phase modulation
D None of these is correct

Q53 : In a first order passive low-pass fifteen (R-C) circuit, the input voltage square wave is fed. The output voltage, with respect to ground, is measured across :

A Supply
B Resister
C Capacitor
D Ground

A It does not provide the target velocity
B It does not provide target range
C It requires a transponder at the target
D It does not provide the target position

Q55 : In an R-L series circuit, the ratio of inductive impedance to resistance is 1/√3. The power factor of the A.C. circuit at steady state is:

A 0.87 lag
C 0.5 lag

Q56 : In television, we use interlacing for the following purpose:

A To provide the illusion of motion
B To ensure that all lines on the screen are scanned
C To simplify the vertical sync pulse train
D To avoid flicker

Q57 : Which statement is not true :

A The phase array radar has very fast scanning compared to other types of radar
B The phase array radar has ability to track and scan simultaneously compared to other types of radar
C The phase array radar has circuit simplicity compared to other types of radar
D The phased array radar has the ability to track many targets simultaneously as compared to other types of radar

Q58 : The satellites used for the purpose of intercontinental communications are called as:

A Intelsat
B Damsat
C Comsat
D Marisat

Q59 : A waveguide can be treated as a :

A Low pass filter
B High pass filter
C Band pass filter
D Band stop filter

Q60 : The radiation power of an antenna which has radiation resistance equal to 500 ohm and fed by 20 A current, will be:

A 100 kW
B 150 kW
C 200 kW
D 250 kW

Q61 : What is the magnitude of the attractive force (in vacuum) between the charge Q1 =3x10-4 C at location (1,2,3) and the charge Q2=-10-4 C at location (2,0,5) ?

A 120 N
B 60 N
C 40 N
D 30 N

Q62 : A full- wave diode bridge rectifier circuit has :

A 3 diodes
B 2 diodes
C 4 diodes
D 8 diodes

Q63 : Which is not an Omni-directional antenna:

A Marconi antenna
B Discone antenna
C Log-periodic antenna
D Half-wave dipole antenna

Q64 : In order to separate the channels in an TDM receiver, we need to use following :

A Band pass filters
B And gates
C Differentiator
D Integrator

Q65 : Which statement is not true ?

A Losses in optical fibers can caused by impurities
B Losses in optical fibers can caused by microbending
C Losses in optical fibers can caused by attenuation in the glass
D Losses in optical fibers can caused by stepped index operation

Q66 : Laser light is:

A Coherent emission
B Stimulated emission
C Spontaneous emission
D Coherent and stimulated emissions

Q67 : The core in optical fiber has following :

A Less refractive index than the air
B Less refractive index than the cladding
C More refractive index than the cladding
D Same refractive index like cladding

Q68 : The electrical torque in terms of supply voltage V in a 3-phase induction motor, is proportional to the following?

A V 2
B V-1
C V1/2
D V

Q69 : The following motor is used for the compressors.

A Reluctance motor
B DC series motor
D Capacitor-start capacitor-run motor

Q70 : Which of the following statement is true ?

A Single-phase induction motor requires only one winding
B Single-phase induction motor can rotate in one direction only
C Single-phase induction motor is self starting
D Single-phase induction motor is not self-starting

Q71 : Which distortion is least significant for the audio amplifiers?

A Frequency
B Phase
C Intermodulation
D Harmonic

Q72 : The following relay is used for protection of motors against overload?

A Thermal relay
B Buchholz relay
C Impedance relay
D Electromagnetic attraction type

Q73 : To charge a feeder cable the following sequence of operation is true :

A Make the isolator followed by make the switch gear
B Make the switch gear followed by make the isolator
C Simultaneously make the isolator and switch gear
D Break the isolator followed by make the switch gear

Q74 : The fuse rating is given in terms of the following :

A kVA
B VAR
C Voltage
D Current

Q75 : Oil switches are applied :

A For low current circuits
B For low voltage circuits
C For high voltages and large current circuits
D For all circuits

Q76 : Which statement is true :

A Reluctance motor can be considered as a variable torque motor
B Reluctance motor can be considered as low torque variable speed motor
C Reluctance motor can be considered as self starting type synchronous motor
D Reluctance motor can be considered as a low noise and slow speed motor

Q77 : Which motor has series characteristics :

B Capacitor start motor
C Repulsion motor
D None of these is correct

Q78 : The variable speed operation is desired for the following application :

A Water pump
B Refrigerator
C Ceiling fan
D Exhaust fan

Q79 : Given that X and Y are two independent Gaussian random variables, each one has average value=0, and variance = , then the joint density function can be defined as :

A f(x,y) = (f(x))/(f(y))
B f(x,y) = f(x) f (y)
C f(x,y) = f(x) -f (y)
D f(x,y) = f(x) +f (y)

Q80 : The material used for insulating in a cable should have the following property :

A Low cost
B High dielectric strength
C High mechanical strength
D All options are correct

Q81 : If the length of a cable is doubled then its capacitance will be :

A One-fourth
B One-half
C Double
D Remain unchanged

Q82 : Which transmission system has skin effect absence, less line cost, low corona effect?

A HVDC
B EHV-AC
C UHB-AC
D HVDC and EHV-AC

Q83 : The load curve is used for

A Deciding schedule of generating units
B Deciding sizes of generating units
C Deciding total installed capacity of the plant
D Deciding schedule and sizes of the generating units and capacity of the plant

Q84 : The circuit given below shows :

A A logarithmic amplifier
B An integrator
C A differentiator
D A clamper

Q85 : An ideal voltage amplifier has :

A Input resistance = 0, Output resistance =
B Input resistance = 0, Output resistance = 0
C Input resistance = , Output resistance = 0
D Input resistance = , Output resistance =

Q86 : Which statement is true :

A A clipper circuit may generate harmonics B A clipper circuit increases the RMS value of the signal
C A clipper circuit improves the power factor of the linear passive load
D A clipper circuit increases the load VA rating of the linear passive load

Q87 : In order to sustain the oscillations, the Barkhausen criteria states that :

A The loop gain of the circuit should be negligible
B The loop gain of the circuit should be equal to 1 with phase shift 180 degree lagging
C The phase shift around the circuit should be 90 degree lag
D None of these is correct

Q88 :

A T = XZ+X
B T= Z+XY
C T=X +XY
D T=X +X

Q89 : Which interrupt is unmaskable interrupt ?

A INTR
B RST 7.5
C TRAP
D RST 5.5

Q90 : Gray code for number 4 is given by,

A 0111
B 0110
C 0101
D 0100

Q91 : Which relation is not true in Boolean algebra ?

A A(BC) = (AB)C
B A(B + C) = AB + AC
C A + AC = A
D A(A + C) = 1

Q92 : The value of of a BJT is :

A >1

Q93 : The enhancement type MOSFET is known as :

A N-type MOSFET
B P-type MOSFET
C Normally off MOSFET
D Normally on MOSFET

Q94 : The following circuit is a sequential circuit :

A AND gate
B NAND gate
C Bistable multivibrator
D EX-OR gate

Q95 : The nature of transconductance curve of a JFET is :

A Straight line
B Parabolic
C Hyperbolic
D Inverted V-type

Q96 : Which diode works under forward-biased condition :

A Photo diode
B Zener diode
C Light emitting diode
D Varactor diode

Q97 : Which statement is true ?

A Hall effect can be used to measure magnetic field intensity
B Hall effect can be used to measure electric field intensity
C Hall effect can be used to measure electric and magnetic field intensities
D Hall effect can be used to measure carrier concentration

Q98 : The most heavily doped region of a transistor is :

A Base
B Collector
C Emitter
D None of these is correct

Q99 : Which is true statement ?

A A bistable multivibrator is a free-running oscillator
B A bistable multivibrator is a triggered oscillator
C A bistable multivibrator is a saw tooth wave generator
D A bistable multivibrator is a crystal oscillator

Q100 : BJT is considered better than MOSFET when :

A There is a requirement of low cost
B There is a requirement of low power dissipation
C There is a requirement of high noise margin
D None of these is correct