Steel Authority Of India Limited (SAIL) Management Trainee MT Electronics Engineering Paper-2010

Steel Authority Of India Limited (SAIL)

Management Trainee

MT Electronics Engineering Paper-2010

1.Two coils in differential connection have self-inductance of 2 mH and 4 mH and a mutual inductance of 0.15 mH. The equivalent inductance of the combination is

• 5.7 mH
• 5.85 mH
• 6 mH
• 6.15 mH.

2.Two point charges Q and -Q are located on two opposite corners of a square as shown in figure. If the potential at the corner A is taken as 1V, then the potential at B, the center of the square will be

• Zero
• (1/2)^1/2V
• 1 V
• (2)^1/2V

3.Opto-couplers combine

• SITs and BJTs
• IGBTs and MOSFETS
• Power transformers and silicon transistor
• Infrared light-emitting diode and a silicon photo transistor

4.The difference between the indicated value and the true value of a quantity is known as

• Gross error
• Absolute error
• Dynamic error
• Relative error

5.The principles of homogeneity and super-position are applied to :

• linear time variant systems
• non-linear time variant systems
• linear time invariant systems
• non-linear time invariant systems.

6.In a 8085 microprocessor system with memory mapped I / 0,

• I / 0 devices have 8-bit addresses
• I / 0 devices are accessed using IN and OUT instructions
• there can be a maximum of 256 input devices and 256 output devices.
• arithmetic and logic operations can be directly performed with the I / 0 data.

7. The transistor shown in figure below, is biased

• at cut-off
• at saturation
• well into saturation
• well into cut-off

8.In any transmitting antenna system, efficiency primarily depends upon

• ohmic losses of various conductors
• radiation resistance
• ground conductivity
• atmospheric conditions.

9.An instruction used to set the carry Flag in a computer can be classified as

• data transfer
• arithmetic
• logical
• program control

10. The binary representation of 5.375 is

• 111.1011
• 101.1101
• 101.011
• 111.001

11. Dislocations in materials are

• point defect
• line defect
• planer defect
• surface defects.

12.In TV system, vertical pulses are separated out from horizontal pulses by the use of

• integrator
• differentiators
• sweep credit
• sync separator.

13.Frequency in the UHF range propagate by means of

• Ground waves
• Sky waves
• Surface waves
• Space waves.

14.200 MHz may be classified as

• VHF
• SHF
• UHF
• EHF

15.A communication satellite is a repeater between

• a transmitting station and a receiving station
• a transmitting station and many receiving stations
• many transmitting stations and many receiving stations
• none of the above

16.The power in a series R-L-C circuit will be half of that at resonance when the magnitude of the current is equal to

• V/2R
• V/(3R)^1/2
• V/(2R)^1/2
• 0

17. The efficiency of a chopper can be expected in the range

• 50 to 55 percent
• 65 to 72 percent
• 82 to 87 percent
• 92 to 99 percent

18.Which one out of the following instruments should be used to measure 600kV a.c.voltages ?

• Hot wire instrument
• Electrostatic voltmeter
• Moving coil voltmeter
• Moving iron voltmeter

19.The following programme is run on an 8085 microprocessor,
                        Memory address in Hex          Instruction
                                    2000                            LXI SP, 1000
                                    2003                            PUSH H
                                    2004                            PUSH D
                                    2005                            CALL 2050
                                    2008                            POP 2050
                                    2009                            HIT
As the completion of execution of the program, the program the program counter of the 8085 contains ………, and the stack pointer contains ……..

• 2050, OFFC
• 2251, OFFC
• 1025, OCCF
• 1025, OCCF

20.The smallest change in sound intensity that can be detected

• 1 dB
• 3 dB
• 10 dB
• 20 dB.

21.In a generic microprocessor, instruction cycle time is

• shorter than machine cycle time
• larger than machine cycle time
• exactly double the machine cycle time
• exactly the same as the machine cycle time

22. The value of M in the end will be
                        Do   100   I = 1, 2
                        DO   200   J = 1, 2
                                        M = M + I + J
                        200   CONTINUE
                        100   CONTINUE
                                    STOP
                                    END

• 10
• 11
• 12
• 14

23.Resistivity of electrical conductors is most affected by

• temperature
• pressure
• composition
• all of the above.

24.In CCIR B-system of TV, blanking pulse is placed during

• equalizing pulse
• retrace interval between each line
• retrace period of vertical line
• none of the above.

25.The polarization required in ground wave propagation is

• Horizontal (linear)
• vertical (linear)
• Circular
• Elliptical

26. Multicavity Klystron

• is not a microwave device
• is not a good low level amplifier because of noise
• is not suitable to pulse operation
• has a high repeller voltage to insure small transit time

27. Transponder comprises of

• Transmitter
• Receiver
• Antenna
• a, b, c combined

28.Which of the following regulator provides output voltage polarity reversal without a transformer

• Buck regulator
• Boost regulator
• Buck-boost regulator
• Cuk regulator

29.The deflection of hot wire instrument depends on

• RMS value of alternating current
• voltage
• average value of a.c. current
• instantaneous value of a.c. current

30. Dual slope integration type Analog-to-Digital converters provide

• higher speeds compared to all other types of A / D converters
• very good accuracy without putting extreme requirements on component stability
• poor rejection of power supply hums
• better resolution compared to all other types of A / D converters for the same number of bits.

31.The frequency modulated (FM) radio frequency range is nearly

• 250 - 300 MHz
• 150 - 200 MHz
• 90 - 105 MHz
• 30 - 70 MHz

32.A 32 bit microprocessor has the word length equal to

• 2 bytes
• 1 byte
• 4 bytes
• 8 bytes

33.Line imperfection in a crystal is called

• Schottky defect
• Frenkel defect
• edge dislocation
• Miller defect.

34.The function of diplexer bridge in a TV transmitter is

• to prevent the loading of several transmitters by video transmitter
• to increase the bandwidth
• to increase the power output
• to increase the efficiency of transmission.

35.Sometimes microwave signals follow the earth’s curvature. This due to

• Ionospheric reflection
• Faraday rotation
• Ducting
• Ionospheric scatter.

36.The modes in a reflex Klystron

• give the same frequency but different transit time
• result from excessive transit time across the resonator gap
• are caused by spurious frequency modulation
• are just for theoretical considerations.

37.The capacity of a channel is

• number of digits used in coding
• volume of information it can take
• maximum rate of information transmission
• bandwidth required for information

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

STEEL AUTHORITY OF INDIA LIMITED

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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