SAIL MANAGEMENT TRAINEE EXAM PAPERS I SAIL ELECTRONICS AND COMMUNICATION EXAM PAPERS I SAIL ELECTRONICS SAMPLE PAPERS I

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Sample Exam Papers

Electronics & Communication

Q.1.If the voltage applied across a capacitance is triangular in waveform then the waveform of the current is

• Triangular
• Trapezoidal
• Sinusoidal
• Rectangular

Q.2.One of the following statement which is true for relative dielectric constant is -

• It is dimensionless
• It is not equal to unity for vacuum
• It’s value for all substances is less than one
• None

Q.3.Pure metals generally have

• high conductivity and low temperature coefficient
• high conductivity and large temperature coefficient
• low conductivity and zero temperature coefficient
• low conductivity and high temperature coefficient

Q.4.For small size, high frequency coils, the most common core material is

• Air
• Ferrite
• Powdered ion
• Steel

Q.5.For an abrupt junction Varactor diode,the dependence of device capacitance (C) on applied reverse bias (V) is given by

• C a V1/3
• C a V-1/3
• C a V1/2
• C a V-1/2

Q.6.A superconductor is a

• A material showing perfect conductivity and Meissner effect below a critical temperature
• A conductor having zero resistance
• A perfect conductor with highest dimagnetic susceptibility
• A perfect conductor which becomes resistive when the current density through it exceeds a critical value

Q.7.When a semiconductor based temperature transducer has a temperature coefficient of –2500 mV/0C then this transducer is indeed a

• Thermistor
• Forward biased pn junction diode
• Reverse biased pn junction diode
• FET

Q.8.The location of lightning arrestor is -

• Near the transformer
• Near the circuit breaker
• Away from the transformer
• None

Q.9.Time constant of an RC circuit increases if the value of the resistance is -

• Increased
• Decreased
• Neither a nor b
• Both a and b

Q.10.Intrinsic semiconductors are those which -

• Are available locally
• Are made of the semiconductor material in its purest from
• Have more electrons than holes
• Have zero energy gaps

Q.11.The primary control on drain current in a JFET is exerted by -

• Channel resistance
• Size of depletion regions
• Voltage drop across channel
• Gate reverse bias

Q.12.The electrical conductivity of metals which is expressed in ohm-1 m-1 is of the order of -

• 1010
• 105
• 10-4
• 10-6

Q.13.When biased correctly, a zener diode –

• acts as a fixed resistance
• has a constant voltage across it
• has a constant current passing through it
• never overheats

Q.14.The current amplification factor adc is given by –

• IC/IE
• IC/IB
• IB/IC
• IB/IC

Q.15.Compared to bipolars, FETs have

• high input impedance
• low input impedance
• same input impedance
• none

Q.16.The source-drain channel of JFET is -

• ohmic
• bilateral
• unilateral
• both a and b

Q.17.A diac is equivalent to a -

• Pair of SCRs
• Pair of four layer SCRs
• Diode and two resistors
• Triac width

Q.18.When a sample of N type semiconductor has electron density of 6.25 ´1011 /cm3 at 300K and if the intrinsic concentration of carriers in this sample is 2.5 ´ 1013/cm3 then the hole density will be –

• 106/cm3
• 103/ cm3
• 1010/ cm3
• 1012/ cm3

Q.19.When the two networks shown in fig. are equivalent with respect to the terminals 1 and 2 at all frequencies then the values of CA, LB, LC and CC will be –

• 0.5, 0.33, 6, 0.166
• 0.5, 3, 6, 0.66
• 0.5, 3, 3, 2
• 0.5, 3, 6, 0.166

Q.20.Poles and zeros of a driving point function of a network are simple and interlace on the jw axis.The network consists of elements –

• R and C
• L and C
• R and L
• R, L and C

Q.21.The statement 'In any network of linear impedances, the current flowing at any point is equal to the algebraic sum of the currents caused to flow at that point by each of the sources of emf taken separately with all other emf's reduced to zero’ represents -

• Kirchhoff's law
• Norton's theorem
• Thevenin's theorem
• Superposition theorem

Q.22.One of the following modes which has the characteristics of attenuation becoming less as the frequency is increased and is attractive at icrowave frequencies of circular cylindrical wave guides is –

• TE1 mode
• TM01 mode
• TE01 mode
• Higher order mode

Q.23.A two-port network is symmetrical if –

• z11z22 – z12z21 = 1
• h11h22 – h12h21 = 1
• AD – BC = 1
• y11y22 – y12y21 = 1

Q.24.For transmission line load matching over a range of frequencies,it is best to use

• a balun
• a broad band directional coupler
• a double stub
• a single stub of adjustable position

Q.25.The poles and zeros of a driving point function of a network are simple and interlace on the negative real axis with a pole closest to the origin. It can be realised -

• by an LC network
• as an RC driving point impedance
• as an RC driving point admittance
• only by an RLC network

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