Friday, December 3, 2010

BSNL TTA Previous Question Paper 2007


Network Filters and Transmission Lines


Number of Questions: 50

Maximum Marks: 250

Time Allowed: 90 Minutes

Negative Marking: Yes


1. Pick up wrong statement

(a) A group of interconnected individual components known as circuit elements is called a network.

(b) A humped network is an arrangement of physically separate resistors, inductors and capacitors.

(c) Distributed network is one, which the resistive, inductive and capacitive effects are inseparable for network analyses.

(d) A branch is a network having four elements.

2. Kirchoff’s laws for networks are:

(a) The algebraic sum of branch currents meeting at any node is zero.

(b) The algebric sum of voltage drops in any set of branches forming a closed circuit or loop must be equal to zero.

(c) Both (a) and (b)

(d) Neither (a) and (b)

3. Mutually coupled circuit is a circuit which is:

(a) Bilateral

(b) Unilateral

(c) None of these

(d) Either (a) or (b)

4. Duality is a

(a) Transformation in which current and voltages are interchanged

(b) Active sources become passive sources

(c) Passive sources become active sources

(d) Both (b) and (c)

5. Combined inductance of two inductors L1 and L2 connected and voltages are interchanged

(a) L1 + L2

(b) (L1 + L2)/ L1

(c) (L1 + L2) / (L1 X L2)

(d) (L1 X L2) / (L1 + L2)

6. Normal analysis techniques are based on

(a) Thevenin’s theorem

(b) Tellegan’s theorem

(c) Superposition theorem

(d) Kirchoff’s Law

7. Two voltage sources can be connected in parallel when they are equal in

(a) Magnitude

(b) Frequency

(c) Phase

(d) All the above

8. The kirchoff’s law fail in

(a) Linear circuits

(b) Non-linear circuits

(c) Lumped parameter circuits

(d) Distributed parameter circuits

9. Which of the following is a nonreciprocal network ?

(a) A network consisting of all resistances

(b) A network consisting of all capacitances

(c) A network consisting of all inductances

(d) A transistor model

10. When two systems obey equations of the same form the systems are said to be

(a) Similar system

(b) Identical system

(c) Analogous system

(d) Digital system

11. For a highly selective circuit

(a) It must have large value of Q

(b) It must have high value of capacitance to produce resonance at fixed frequency

(c) Either (a) or (b)

(d) Neither (a) nor (b)

12. A network consisting of four terminals is called a

(a) One port network

(b) Two port network

(c) Four port network

(d) None of the above

13. Driving point of a network is

(a) A port where voltage or current source is connected

(b) A terminal where load is connected

(c) A port where load is connected

(d) None of the above

14. Ceramic filters are similar in construction to

(a) Crystal filters

(b) Crystal ladder filters

(c) Crystal lattice

(d) Mechanical filters

15. When two port networks are connected in parallel the resultant

(a) Z parameters are the some of individual parameters

(b) Y- parameters are the some of individual parameters

(c) Both (a) and (b)

(d) Neither (a) nor (b)

16. Electric wave filters

(a) Allow electric signals with specified frequency range

(b) Suppress signals outside a specified range

(c) Both (a) and (b) occurs simultaneously

(d) Either (a) or (b) occur at a time

17. A cascade connection of low pass filter and high pass filter is called

(a) Band pass filter

(b) Band elimination filter

(c) Neither (a) nor (b)

(d) Both (a) and (b)

18. The response of a network is decided by the location of

(a) Its poles

(b) Its zeros

(c) Either (a) nor (b)

(d) Both (a) and (b)

19. Example of two port network is

(a) Transformer

(b) Transmission line

(c) Bridge circuit and transistor circuit

(d) All of the above

20. The circuit whose properties are same in either direction is called

(a) Universal circuit

(b) Reversible circuit

(c) Unilateral circuit

(d) Bilateral circuit

21. Distortion in transmission line is due to

(a) Delay distortion

(b) Phase distortion

(c) Frequency distortion

(d) All the above

22. The general parameters distributed along a transmission line are

(a) R&L only

(b) L&C only

(c) C&G only

(d) R, L, C&G

23. Phase distortion is prominently caused by

(a) circuit transients

(b) non linear characteristics

(c) linearity

(d) none

24. The voltage or current from the receiving end towards the sending end, decreasing in amplitude with increasing distance from the load is called

(a) incident wave

(b) medium wave

(c) reflected wave

(d) none of above

25. E.M. Waves of UHF is propagated efficiently via

(a) parallel wire transmission lines

(b) open wire transmission lines

(c) wave guides

(d) coaxial cables

26. Norton theorem is valid for network containing only

(a) linear elements

(b) no linear elements

(c) resistance

(d) reactance

27. The maximum power is absorbed by one network from other, joined to it at two terminals when the impedance of one is

(a) complex conjugate of other

(b) square root of other

(c) same as other

(d) none of above

28. The decrease in effective conductor cross section at high frequencies

(a) decrease the conductor resistance

(b) increase the conductor resistance

(c) no change in conductor resistance

(d) none of above

29. Voltage standing wave ratio lies in the range

(a) 0 to 1

(b) 1 to infinity

(c) 0 to infinity

(d) -1 to +1

30. Attenuators have applications

(a) in AC circuits only

(b) in DC circuits only

(c) in AC as well DC circuits

(d) in low frequency circuits only

31. In an network

(a) the number of tree branches is equal to the number of links

(b) the number of tree branches cannot be equal to the number of links

(c) the number of tree branches has no relation with the number of links branches

(d) none of these

32. In open line transmission systems, attenuation is more at

(a) lower frequencies

(b) medium frequencies

(c) higher frequencies

(d) remains constant

33. a power ratio 100 is equivalent to

(a) 10 dB

(b) 20 dB

(c) 50 dB

(d) 100 dB

34. The velocity factor for small widely spaced conductors such as open wire line in air is very nearly

(a) 0.66

(b) 0.98

(c) 0.82

(d) 0.76

35. Transmission of power to a load over a transmission line achieves optimum value when standing wave ratio (SWR) becomes

(a) 2 : 1

(b) 1 : 2

(c) 1 : 1

(d) 1 : 10

36. The VSWR in a short circuited loss less transmission line equals

(a) infinity

(b) unity

(c) zero

(d) none of above

37. The velocity factor of a transmission line

(a) is always greater than unity

(b) depend upon the permittivity of the surrounding medium

(c) is lease for air medium

(d) is governed by skin effect

38. Which of the following is not correct

(a) voltage source is an active element

(b) current source is a passive element

(c) resistance is a passive element

(d) conductance is a passive element

39. A network is said to be nonlinear if it does not satisfy

(a) superposition condition

(b) homogeneity condition

(c) both superposition and homogeneity conditions

(d) associative condition

40. An capacitor with zero initial condition at t = 0+ act as a

(a) short circuit

(b) open circuit

(c) current source

(d) voltage source

41. An inductor stores energy in

(a) electrostatic field

(b) electromagnetic field

(c) magnetic field

(d) core

42. In series LCR circuits, at resonance,

(a) current is maximum, power factor is zero

(b) current is maximum, power factor is unity

(c) current is minimum, power factor is unity

(d) none of above

43. In an RCL series circuit, during resonance, the impedance will be

(a) zero

(b) minimum

(c) maximum

(d) none of above

44. When a source is delivering maximum power to load, the efficiency of the circuit is always

(a) 50%

(b) 75%

(c) 100%

(d) None of above

45. In a linear network, when the ac input is doubled, the ac output becomes

(a) two times

(b) four times

(c) half

(d) one forth

46. A passive network has

(a) current sources but no voltage sources

(b) voltage sources but no current sources

(c) both current and voltage sources

(d) no voltage or current sources

47. Two resistances are connected in parallel and each dissipates 50 waits. The total power supplied by the source is

(a) 25 watts

(b) 50 watts

(c) 100 watts

(d) 200 watts

48. Three bulbs of 60 watts each are connected is parallel across 220v, 50 Hz supply. If one bulb burns out

(a) only remaining two will operate

(b) remaining two will not operate

(c) all of three will operate

(d) there will be heavy current from the supply

49. The amplitude of an audio signal is 10 and that of carrier wave is 50. Percentage modulation is:

(a) 0.2

(b) 20

(c) 5

(d) 60

50. The main advantage of PCM system is:

(a) lower bandwidth

(b) lower power

(c) lower noise

Monday, November 22, 2010

ECIL GRADUATE ENGINEER TRAINEE PREVIOUS PAPER


1. Consider the following expressions indicating the step or impulse response of an initially relaxed control system-

1. (5 – 4e-2+) u(t)
2. (e-2t +5) (u(t))
3 .V(t) + 8e-2t u(t)
4 . V(t) + 4e-2t 4(t)

2. Those which correspond to the step and impulse response of the same system include- 1&3
Which is the following relate to rational transfer function of a system-

1. Ratio of Fourier transform of output to input with zero initial conditions.
2. Ratio of Laplace transform of output to input with zero initial conditions.
3. Laplace transform of system impulse response.
4. Laplace transform of system unit step response select the correct answer using the codes given below.

Codes
a.) 1 and 4
b.) 2 and 3
c.) 1 and 3
d.) 2 and 4

3. For the signal g (t) – 10 cos (50 pt) cos2 (150at)
The Nyquist sampling state in t seconds is

a.) 150 samples per second
b.) 200 samples per second
c.) 300 samples per second
d.) 350 samples per second

4. In the case of a 70 MHz 1F carries for a transponder band width of 36 MHz; energy must lie between – MHz.

a.) 34 and 106
b.) 52. And 88
c.) 106 and 142
d.) 34 and 142

5. Radar used to eliminate clutter in navigational application is

a.) Pulse radar
b.) Tracking radar
c.) MTI radar
d.) Mono pulse radar

6. The 1.55 mm windows is not yet in use with fiber optic systems because –

a.) The attenuation is higher than at 0.85 mm
b) The attenuation is higher than at 1.3mm
c.) Suitable laser devices have not yet been developed
d.) It does not lend itself to wavelength multiplexing

7. Pre-emphasis in FM systems involves-

a.) Compression of the modulating signal
b.) Expansion of the modulating signal( placementpapers.fresherjobs4u.com)
c.) Amplification of lower frequency components of the modulating signal.
d.) Amplification of higher frequency components of the modulating signal.

8. In a terrestrial microwave system transmission of signals is achieved through-

a.) reflection from the ionosphere
b.) line of sight mode
c) reflection from the ground
d.) diffraction from the stratosphere.

9. Case grain feed is used with a parabolic reflector to

a.) increase the gain of the system
b). increase the bandwidth of the system
c.) reduce the size of the main reflector
d.) allow the feed to be placed at a convenient point.

10. In most microwave communication link rain drop attenuation is caused due to-

a.) scattering of microwaves by water drops of specific size.
b) scattering of microwaves by a collection of droplets acing as a single body.
c.) absorption of microwaves by water and consequent heating of the liquid
d.) absorption of the microwaves by water vapor in the atmosphere.

11. When a (75 – j40)W load is connected to a coaxial line of Z0 = 75 W at 6MHz then the load matching on the line can be accomplished by connecting-

a.) A short – circuited stub at the load
b.)An inductance at the load
c. )A short circuited stub at a specific distance from the load
d.)none of the above

12. As compared to analog multimeters, digital multimeters are -

a.) less accurate
b.) more accurate
c.) equally accurate
d.) none.

13. When a signal of 10 mV at 75 MHz is to be measured then which of the following instruments can be used –

a.) VTVM
b.) Cathode ray oscilloscope
c.) Moving iron voltmeter
d.) Digital multimeter

14. Amplifier of class B has high theoretical efficiency of 78.5 percent because -

a.) It is biased almost to saturation
b.)Its quiescent current is low
c.)It’s output is an exact replica of it’s input
d.)It is biased well below cut off

15. The coupling that produces minimum interference with frequency response is-

a.) Direct coupling
b.)Impedance coupling
c.) R C coupling
d.)Transformer coupling

16. A superconductor is a –

a.) A material showing perfect conductivity and Meissner effect below a critical temperature
b.) A conductor having zero resistance(placementpapers.fresherjobs4u.com)
c.) A perfect conductor with highest di-magnetic susceptibility
d.) A perfect conductor which becomes resistance when the current density through it exceeds a critical value

17. When an inductor tunes at 200 KHz with 624 pF capacitor and at 600 KHz with 60.4 pF capacitor then the self capacitance of the inductor would be –

a) 8.05 pF
b) 10.05pF
c.) 16.01pF
d.) 20.01pF

18. The Q of a radio coil –

a.) is independent of frequency
b.) increases monotonically as frequency increases
c.) decreases monotonically as frequency increases
d.) increases upto a certain frequency and then decreases beyond that frequency

19. When a generator of internal impedance and operating at 1GHz feeds a load via a coaxial line of characteristic impedance 50 ohm then the voltage wave ratio on the feed line is –

a.) 0.5
b.) 1.5
c.) 2.5
d.) 1.75

20. The coding system typically used in digital telemetry is –

a.) PPM (pulse position modulation)
b.) PAM (pulse amplitude modulation)
c.) PCM (pulse code modulation)
d.) PDM (pulse duration modulation)

21. Radiation pyrometers are used for the measurement of temperature in the range of –

a.) -2000C to 5000C
b.) 00C to 5000C
c.) 5000C to 12000C
d.) 12000C to 25000C

22. RF amplifier of an A.M. receiver is normally biased in –

a.) Class ’A’
b.) Class ’b’
c.) Class ’C’
d.) None

23. The value of gate voltage for the operation of enhancement of only N channel MOSFET has to be –

a.) High positive
b.) High negative
c.) Low positive
d.) Zero

ECIL GRADUATE ENGINEER TRAINEE 2007 EXAM PAPER



1. When a inductive coil connected to a 200 V, 50Hz ac supply with 10A current flowing through it dissipates 1000 watts then which of the following will have least value in ohms-

a.) Resistance

b.) Reactance

c.) Impedance

d.) None

2.

Oscillator crystal are made of –

a.) Silicon

b.) Germanium

c.) Quartz

d.) None
3.

For small size, high frequency coils, the most common core material is-

a. )Air

b. )Ferrite

c.) Powdered ion

d.) Steel
4.

If we have a parallel plate capacitor of plate area ’A’ and plate separatoin t and having a capacity C and a metallic plate r of area A and of negligible thickness is introduced in thecapacitor at a distance from either of the two plates as shown in the given figure then the capacity of the capacitor will become –

a.)

b.) C

c.) 2C

d.) 4C
5.

A superconductor is a –

a.) A material showing perfect conductivity and Meissner effect below a critical temperature

b.) A conductor having zero resistance

c.) A perfect conductor with highest di-magnetic susceptibility

d.) A perfect conductor which becomes resistance when the current density through it exceeds a critical value

6.

When an inductor tunes at 200 KHz with 624 pF capacitor and at 600 KHz with 60.4 pF capacitor then the self capacitance of the inductor would be –

a) 8.05 pF

b) 10.05pF

c.) 16.01pF

d.) 20.01pF
7.

Sparking occur when a load is switched off because the circuit has high –

a.) Inductance

b.) Capacitance

c.) Resistance

d.) None
8.

Sparking between contacts can be reduced by inserting a –

a.) Resistance in the line

b.) Capacitor in series with contacts

c.) Capacitor in parallel with contacts

d.) None
9.

RF amplifier of an A.M. receiver is normally biased in –

a.) Class ’A’

b.) Class ’b’

c.) Class ’C’

d.) None
10.

The value of gate voltage for the operation of enhancement of only N channel MOSFET has to be –

a.) High positive

b.) High negative

c.) Low positive

d.) Zero
11.

The input gate current of a FET is –

a.) a few microamperes

b.) negligibly small

c.) a few milliamperes

d.) a few amperes
12.

In the following fig. with R = 30k, the value of current through 2 K resistor is –

a.) 25 mA

b.) 40 mA

c.) 25/16 mA

d.) 10 mA
13.

A step recovery diode –

a.) has on extremely short recovery time

b.) conducts equally well in both directions

c.) is mainly used as a harmonic generator

d.) is an ideal rectifiers of high frequency signals
14.

In order to get maximum undistorted output signal from CE amplifier with VCC 10V, the value of VCE (Q) should be approximately-

a.) 0.1V

b.) 5V

c.) 10V

d) V
15.

In a FET the electrode, which corresponds to collector in bipolar transistor, is –

a.) source

b.) drain

c.) gate

d.) none
16.

The device which acts like an NPN and a PNP transistor connected base to base and emitter to collector is –

a.) Triac

b.) UJT

c.) Diac

d.) SCR
17.

A typical optical fibre has –

a.) High refractive index core and low refractive index cladding

b.) Low refractive index core and high refractive index cladding

c.) Both a and b

d.) None
18.

In the following figure circuit diagram of an op-amp based is shown. The ratio is equal to –

a.) 9

b.) 11

c.) 10

d.) 21
19.

When a loud speaker is connected across the terminals A and B of the network shown in the fig. then its impedance to obtain maximum power dissipation in it will be –

a.) 3 – j1

b.) 3 + j9

c.) 7.5 + j 2.5

d.) 7.5 – j 2.5
20.

In the lattice network, the value of R for the maximum power transfer to the load –

a.) 5

b.) 6.5

c.) 8

d.) 9



21.

For a lossy transmission line short circuited at the receiving end, the input impedance is given by (Z0 is the characteristic impedance, Ö is the propagation constant and l is the length of the line-

a.) Z0 cot h Öl

b.) Z0 cot Öl

c.) Z0 tan h.Ö l

d.) Z0 tan Öl
22.

The approximate thickness of the radome wall should be –

a.) l

b.) l/4

c.) l/2

d.) l/8
23.

A relatively permanent information is stored in

a. ) ROM

b.) RAM

c.) PROM

d.) Volatile memory

24.

The rise time of the RC network shown in the given figure is approximately equal to –

b.) RC

c.) 2RC

d.) 4RC
25.

If in the network shown in the fig. initially a steady state is attained by closing the switch ’s’ and then if the switch is opened at t = 0, then thecurrent i(t) through the inductor will be –

a.) cos50tA

b.) 2A

c.) 2cos100tA

d.) 2sin50tA
26.

When the p network of figure – I and T-network of figure – II are equivalent then the values of R1, R2 and R3 will be respectively –

a) 9W, 6W and 6W

b.) 6W, 6W and 9W

c.) 9W, 6W and 9W

d.) 6W, 9W and 6W
27.

When the impedance matrices of a two port networks are given by and , then if these two networks are connected in series then the impedance matrix of the resulting two-port network will be –

d.) indeterminate
28.

Joule/coulomb is the unit of -

a.) Electric field potential

b.) Potential

c .) Charge

d.) None of the above
29.

The electric field line and equipotential lines-

a.) Are parallel to each other

b.)Are one and same

c.) Cut each other orthogonally

d.)Can be inclined to each other at any angle
30.

For a lossy transmission line short circuited at the receiving end, the input impedance is given by (When Z0 is the characteristic impendence g is the propagation constant and L is the length of the line

31.

When two equal positive point charges are placed along X- axis at X1 and –X1 respectively then the electric field vector at a point P on the positive Y-axis will be directed-

a.) In the +x direction

b.) In the –x direction

c. ) In the +y direction

d.) In the –y direction
32.

The directions of and in TEM mode transmission line with respect to the direction of propagation are-

a.) Both and are transverse to the direction of propagation

b.) is and are transverse and h has a component in the direction of propagation

c.) is entirely transverse and has a component in the direction of propagation

d. ) is entirely transverse and has a component in the direction of propagation
33.

The lowest TM mode in a rectangular waveguide of cross –section a x b with a>b will be-

a.) TM01

b.)TE10

c.) TM112

d.)TE11

34.

When a transmitter in a free space radiates a mean power of ’p’ watts uniformly in all directions then at a distance d sufficiently far from the source in plane the electric field E should be related to p and d as –

35.

. When a dipole antenna was radiating with some excitation in free space radiating a certain amount of the power v if then this antenna is immersed in a lake where water is non-dissipative but has a dielectric constant of 81, then the radiated power with the same excitation will be

a.) Decrease to finite non-zero value

b.)Remain the same

c. )Increase

d.)Decrease to zero
36.

When a (75 – j40)W load is connected to a coaxial line of Z0 = 75 W at 6MHz then the load matching on the line can be accomplished by connecting-

a.) A short – circuited stub at the load

b.)An inductance at the load

c. )A short circuited stub at a specific distance from the load

d.)none of the above
37.

As compared to analog multimeters, digital multimeters are –

a.) less accurate

b.) more accurate

c.) equally accurate

d.) none.
38.

When a signal of 10 mV at 75 MHz is to be measured then which of the following instruments can be used –

a.) VTVM

b.) Cathode ray oscilloscope

c.) Moving iron voltmeter

d.) Digital multimeter
39.

Which of the following statement is true about two wattmeter method for power measurement in three phase current ?

a.) power can be measured using two wattmeter method only for star connected three phase circuits.

b.) when two meter show indentical readings, in the power factor is 0.5.

c.) when power factor is unit, one of the wattmeter reads zero

d.) when the reading of the two wattmeters are equal but of opposite sign, then the power factor is zero –
40.

When a capacitance transducer has two plates of area 5cm2 each, separated by an air gap of 2mm than the displacement sensitivity in pf/cm due to gap change would be –

a.) 11.1

b.) 44.2

c.) 52.3

d.) 66.3
41.

The Q of a radio coil –

a.) is independent of frequency

b.) increases monotonically as frequency increases

c.) decreases monotonically as frequency increases

d.) increases upto a certain frequency and then decreases beyond that frequency
42.

When a generator of internal impedance and operating at 1GHz feeds a load via a coaxial line of characteristic impedance 50 ohm then the voltage wave ratio on the feed line is –

a.) 0.5

b.) 1.5

c.) 2.5

d.) 1.75
43.

The coding system typically used in digital telemetry is –

a.) PPM (pulse position modulation)

b.) PAM (pulse amplitude modulation)

c.) PCM (pulse code modulation)

d.) PDM (pulse duration modulation)
44.

Radiation pyrometers are used for the measurement of temperature in the range of –

a.) -2000C to 5000C

b.) 00C to 5000C

c.) 5000C to 12000C

d.) 12000C to 25000C
45.

In the given figure band structure is shown. It is of –

a.) Gallium Avesenide (GaAs)

b.) Silicon (Si)

c.) Copper (Cu)

d.) Germanium (Ge)
46.

When anode is positive with respect to cathode in an SCR, the numbers of blocked p-n junction is –

a.) 1

b.) 2

c.) 3

d.) 4
47.

The circuit symbol for a GTO is

a. b.

c. d.

48.

In the given fig. mark out the type of Cyclo converters

a.) 1 phase to 1 phase with continuous conduction

b.) 1 phase to 1 phase with discontinuous conduction

c.) step up device

d.) 3 phase to 1 phase device

In the given fig. A-1, C=5, m H and C=20 m F, C is initially charged to 200 V. After the switch.

S is closed at t = 0 the

maximum value of current and the

time at which it reaches this value are respectively.

a.) 400 A, 15.707 mS
49.

b.) 50 A, 30 mS

c.) 100 A, 62.828 mS

d.) 400 A, 31.414 mS

50.

50. In the given circuit the maximum current in the main SCR M can be-

a.) 200 A

b.) 170.7 A

c.) 141.4 A

d.) 70.7 A

51.

The transfer function of an amplifier is given by

The high 3-db frequency of the amplifier will approximately

a.) 5850 KHZ

b.)585 KHZ

c.) 5850 HZ

d.)585HZ

52.

In comparison to full wave rectifier with two diodes the four divide bridge rectifier has the dominant advantage of -

a). Higher current carrying

b.)Lower ripple factor

c.) Higher efficiency

d.)Lower peak increase voltage require

53.

Power output increase in a class-c amplifier-

a.) If the conduction angle decrease

b).If the conduction angle increase

c.) Are not governed by the conduction angle

d.)None of the above
54.

A transistor with hie = 1.5 k and hfe = 75 is used in an emitter follower circuit where R1 and R2 are used for normal biasing . Approximate value of it’s current amplification is-

a.)75

b.)76

c.)75/76

d.)-75
55.

Amplifier of class B has high theoretical efficiency of 78.5 percent because-

a.) It is biased almost to saturation

b.)Its quiescent current is low

c.)It’s output is an exact replica of it’s input

d.)It is biased well below cut off
56.

The coupling that produces minimum interference with frequency response is-

a.) Direct coupling

b.)Impedance coupling

c.) R C coupling

d.)Transformer coupling
57.

In the circuit shown in the given figure Rf provides

a.) Current series feedback

b.)Current shunt feedback

c.) Voltage series feedback

d.)Voltage shunt feedback
58. Mark the correct relation for the junction transistor

59. Data in the serial form can be converted into parallel form by using –

a.) PISO shift register

b.) SOIP shift register

c.) SIPO shift register

d.) POIS shift register

60.

PROMs are used to store-

a.) bulk information

b.) information to be accessed rarely

c.) sequence information

d.) relatively permanent information
61.

The horizontal axis in a 3 bit unipolar D/A converter represents-

a.) Output bit combination

b.) analog output voltage

c.) input bit combination

d.) none of the above
62.

’Not allowed’ condition in NAND gate SR flip flop is –

a.) s = 0, R = 0

b.) s = 1, R = 1

c.) s = 0, R = 1

d.) s = 1, R = 0
63.

Name the fastest logic family-

a) TTL

b.) RTL

c.) DCTL

d.) ECL
64.

Equation corresponding to De Morgan’s theorem in Boolean Algebra is –

a.) (A+B) (A+B) = AA + AB + BA + BB

c.) A + AB = A

d.) None of the above
65.

In the given fig find radix of the system –

a.) 2
b.) 4

c.) 6

d.) 8

66.

Modems are used for data transmission telephone lines to –

a.) increase the transmission capacity

b) improve noice performance

c.) incorporate error control coding

d.) eliminate dc component in the transmitted signal
67.

The figure of a control system is shown. The maximum value of gain K for which the system is stable is-

a.)

b.) 3

c.) 4

d.) 5
68.

Identify the example of open-loop system-

a.) A windscreen wiper

b.) Aqualung

c.) Respiratory system of an animal

d.) A system for controlling Anti-rocket missiles.
69.

Consider the following expressions indicating the step or impulse response of an initially relaxed control system-

1. (5 – 4e-2+) u(t)

2. (e-2t +5) (u(t))

3 .V(t) + 8e-2t u(t)

4 . V(t) + 4e-2t 4(t)

Those which correspond to the step and impulse response of the same system include-

a.) 1&3

b.) 1&4

c.) 2&4

d.) 1&4

70.

A system is described by

To test its stability by Lyapunov’s method the following V functions are considered.

Mark the most suitable V-function in this case-

a.) Only V1

b.) Only V2

c.) Both V1 and V2

d.) Neither V1 nor v2

71.

Identity the polar plot of a typical type zero system with open loop transfer function

72.

The scattering matrix of a magic –tee shown in the given figure is-

73.

Which is the following relate to rational transfer function of a system-

1. Ratio of Fourier transform of output to input with zero initial conditions.

2. Ratio of Laplace transform of output to input with zero initial conditions.

3. Laplace transform of system impulse response.

4. Laplace transform of system unit step response select the correct answer using the codes given below.

Codes

a.) 1 and 4

b.) 2 and 3

c.) 1 and 3

d.) 2 and 4
74.

For the signal g (t) – 10 cos (50 pt) cos2 (150at)

The Nyquist sampling state in t seconds is

a.) 150 samples per second

b.) 200 samples per second

c.) 300 samples per second

d.) 350 samples per second
75.

In the case of a 70 MHz 1F carries for a transponder band width of 36 MHz; energy must lie between – MHz.

a.) 34 and 106

b.) 52. And 88

c.) 106 and 142

d.) 34 and 142
76.

Radar used to eliminate clutter in navigational application is –

a.) Pulse radar

b.) Tracking radar

c.) MTI radar

d.) Mono pulse radar
77.

The 1.55 mm windows is not yet in use with fiber optic systems because –

a.) The attenuation is higher than at 0.85 mm

b) The attenuation is higher than at 1.3mm

c.) Suitable laser devices have not yet been developed

d.) It does not lend itself to wavelength multiplexing
78.

Pre-emphasis in FM systems involves-

a.) Compression of the modulating signal

b.) Expansion of the modulating signal

c.) Amplification of lower frequency components of the modulating signal.

d.) Amplification of higher frequency components of the modulating signal.
79.

In a terrestrial microwave system transmission of signals is achieved through-

a.) reflection from the ionosphere

b.) line of sight mode

c) reflection from the ground

d.) diffraction from the stratosphere.

80.

Casse grain feed is used with a parabolic reflector to

a.) increase the gain of the system

b). increase the bandwidth of the system

c.) reduce the size of the main reflector

d.) allow the feed to be placed at a convenient point.

81.

In most microwave communication link rain drop attenuation is caused due to-

a.) scattering of microwaves by water drops of specific size.

b) scattering of microwaves by a collection of droplets acing as a single body.

c.) absorption of microwaves by water and consequent heating of the liquid

d.) absorption of the microwaves by water vapor in the atmosphere.

82.

Circuit in the given figure represents. –

a.) an astable multivibrator

b.) A monostable multivibrator

c.) Voltage controlled oscillator

d.) Ramp generator

83.

. . D = r is-

a.) Maxwell’s 1st equation

b.) Maxwell’s II equation

c.) Maxwell’s III equation

d.) Maxwell’s IV equation

84.

In a rectangular wave-guide which TM mode exists-

a.) TM00

b.) TM01

c.) Tm10

d.) TM11

85.

In directional coupler a portion of power two velliry fram port 1) to port 2) is coupled to.

a). port 4

b). port 3

c.) port 2.

d.) port 3 & 4.

86.

For high power i.e. 10 w to 50 kw measurement –

a.) Barometer are used

b.) Thermisters are used

c.) Calorimetric technique

d.) Calorimetric watt meter technique used
87.

The difference between TWT & klystron is –

a.) In TWT electrons are in contact with RF field for long time & in klystron for short time

b.) In klystron electrons are in contact with RF field for long time & in TWT for short time

c.) In klystron there is no contact in RF field & electrons while in TWT there is contact

d.) In TWT phase is no contact is RF field & electrons while in klystron there is contact
88.

Which one is most suitable for transmission through wave guide-

a.) Hown antennas

b.) Bioconical antennas

c.) helical antenna

d. )Discone
89.

The skip distance of microwave is given by –

a.)

b. )

c.)

d.)
90.

How many general purpose registers 8085mp-

a.) 4

b.) 6

c.) 8

c.) 10
91.

8085 mP has no. of addressing modes-

a.) 2

b.) 3

c.) 4

d.) 5
92.

What will be status of z and c y flag after execution of SUB A instruction

a.) z = 0, cy = 0

b.) z = 0, cy = 1

c.) z = 1, cy = 0

d.) z = 1, cy = 1

93.

Microprocessor accept interrupt only if.

a.) interrupt flip flop disabled.

b.) when INTA signal is low.

c. ) interrupt flip flop enabled.

d.) none of above.
94.

Microprogramming is a technique

a.) for programming the microprocessor

b.) for writing small programs efficiently

c.) for programming the control steps of computer

d.) for programming o/p / i/p
95.

High level programs like C are converted into machine language with the help of

a.) interpreter

b.) compiler

c.) operating

d.) system
96.

(10110011)2 = (?)8

a.) 253

b.) 263

c.) 273

d.) 283
97.

A Not gate at the output of AND gate converts AND gate into-

a.) NAND

b.) NOR

c.) AND

d.) NOPE.
98.

The O/P of a logic gate is the gate must be-

a.) AND

b.) OR

c.) NAND

d.) X-OR
99.

A symbol of JK flip flop is-

100.

A demultiplener-

a.) has multiple i/p and single o/p

b.) has multiple i/p and multiple o/p

c.) has multiple i/p and multiple o/p

d.) has single i/p and single o/p
101.

. Which of the following best describes the authour`s attitude toward fairy tales ?

a.) fascination

b.) open approval.

c.) Indulgent tolerance.

d.) Scornful.
102.

What type of sentence is this ?

Hurray! We won the match

a.) Exclamatory

b.) assertive

c.) Negative

d.) Affirmative
103.

Before which of the following word will you put ’a’

a.) hour

b.) M. A.

c.) Umbrella

d.) Man
104.

The noun form of ’fresh’ is –

a.) freshly

b.) freshen

c.) fresheners

d.) fresh itself
105.

The word ’clang’ is an example of –

a.) Simile

b.) inversion

c.) onomatopoeia

d.) irony
106.

The Forbes magazine acclaimed Azim Premji as richest India’s is the chairman of-

a.) Pentafour software

b) Infosys

c.) IBM

d.) Wipro
107.

Bharat Ratna award for the year 2001 goes to-

a.) Lata Mangeshkar and Zakeer Hussain

b.) Zakeer Hussain and Bismillah Khan

c.) Bismillah Khan and Lata Mangeshkar

d.) Lata Mangeshkar and Ustad Amzad Ali Khan
108.

Mr. George W-Bush takes over as —— President of the united states of America succeeding Mr. Bill Clinton-

a.) 42nd

b.) 43rd

c.) 40th

d.) 45th
109.

New Chief Minister of Pondicherry is-

a.) T. Venkat Naidu

b.) K. Hari Harh

c.) N. Rengaswany

d.) M. Mudliar
110.

No court has the jurisdiction to interfere with the election process once set in motion by the Election commission. This is enshrined in Article-

a.) 311

b.) 329

c.) 356

d.) 365
111.

Ostrich is a-

a.) Running bird

b.) Flying bird

c) Swimming bird

d.) Migratory bird
112.

The main atmospheric gas responsible for green house is-

a.) Oxygen

b.) Nitrogen

c.) Ozone

d.) Carbon-dioxide
113.

Which of the following is not a Kharif Crop-

a.) Rice

b.) groundnut

c.) Sugarcane

d.) gram
114.

The function of World Bank is to-

a.) Help in reconstruction and development of world economy

b.) Facilitate poor countries to trade on concessional rates

c.) Promote growth of international trade and equilibrium in balance of payments

d.) Ease trade barriers and establish rule of fair trade
115.

Speed of sound is maximum in-

a. )Water

b.) Air

c.) Steel

d.) Vacuum
116.

“Long years ago we made a trust with destiny.” Whose words are these-

a.) Subhash Chandra Bose

b.) Jawaharlal Nehru

c.) Lajpat Rai

d.) Bhagat Singh
117.

Durand cup is associated with-

a.) Hockey

b.) Tennis

c.) Football

d.) Badminton
118.

Rabindranath Tagore was awarded the Nobel Prize in literature in the year.

a.) 1908

b.) 1910

c.) 1913

d.) 1914
119.

India successfully conducted its first underground nuclear experiment at Pokhran in Rajas than on-

a.) May 18, 1975

b.) May 20, 1974

c) May 17, 1974

d.) May 17, 1974
120.

An emergency loan of $ 500 million to help reconstruct infrastructure in earth quake devastated Gujarat approved by-

a.) Asian development Bank

b.) World Bank

c.) Swiss Bank

d.) Reserve Bank of India

ECIL GRADUATE ENGINEER TRAINEE PREVIOUS PAPER


Part 1
1.The current I in the given network.
a) 1A b) 3A c) 5A d) 7A


2.For the Delta- Wye transformation in given figure, the value of the resistance R is.
a) 1/3 ohms b) 2/3 ohms c) 3/2 ohms d) 3 ohms


3.In the given network, the Thevenin’s equivalent as seen by the load resistance Rl is
a) V=10 V, R= 2ohms b) V=10V, R=3 ohms c) V=15V, R= 2ohms d) V=15V, R=3 ohms


4.The current I in a series R-L circuit with R=10 ohms and L=20mH is given by i=2sin500t A. If v is the voltage across the R-L combination then i
a) lags v by 45 degree b) is in-phase with v c) leads v by 45 d) lags v by 90


5.In thr given network, the mesh current I and the input impedance seen by the 50 V source, respectively, are
a) 125/13 A and 11/8 ohms b) 150/13 A and 13/8 ohms c) 150/13 A and 11/8 ohms d) 125/13 A and 13/8 ohms


6.A voltage sourcehaving a source impedance Z = R + jX can deliver maximum Average power to a load impedance Z, when
a) Z = R + jX b) Z = R c) Z = jX d) Z = R –jX


7.In the given circuit, the switch S is closed at t=0. Assuming that there is no initial Charge in the capacitor, the current i(t) for t>0 is
a) V/R e^ (-2t/RC) b) V/R e^ (-t/RC) c) V/2R e^ (-2t/RC) d) V/2R e^ (-t/RC)


8.For the circuit in given figure, if e(t) is a ramp signal, the steady state value of the Output voltage v(t) is
a) 0 b) LC c) R/L d) RC


9.For the series RLC circuit in given figure, if w=1000 rad/sec, then the current I (in Amperes) is
a) 2 ∟-15 b) 2 ∟15 c) √2∟-15 d) √2∟15


10.The Y-parameter matrix (mA/V) of the two-port given network is
a) [2 -1 -1 2] b) [2 1 -1 2] c) [1 -2 -1 2] d) [2 1 1 2]

11.The maximum number of trees of the given graph is
a) 16 b) 25 c) 100 d) 125


12.Given figure shows a graph and one of its trees. Corresponding to the tree, the group of branches that CAN NOT constitute a fundamental cut set is
a) 1,2,3 b) 1,4,6,8,3 c) 5,6,8,3 d) 4,6,7,3


13.The Y-parameter matrix of a network is given by Y=[1 1 -1 1] A/V. The Z11 parameter of the same network is
a) ½ ohms b) 1/√2 ohms c) 1 ohms d) 2 ohms


14.For the given circuit, the switch was kept closed for a long time before opening it at t=0. The voltage v(0+) is
a) -10 V b) -1 V c) 0V d) 10 V


15.The input impedance of a series RLC circuit operating at frequency W=√2w, w being the resonant frequency, is
a) R-j(wL/√2) ohms b) R+j(wL/√2) ohms c) R-j√2wL ohms d) R-j√2wL ohms


16.The threshold voltage V is negative for
a) an n-channel enhancement MOSFET b) an n-channel depletion MOSFET c) an p-channel depletion MOSFET d) an p-channel JFET


17.At a given temperature, a semiconductor with intrinsic carrier concentration ni= 10 ^ 16 / m^3 is doped with a donor dopant of concentration Nd = 10 ^ 26 /m^3. Temperature remaining the same, the hole concentration in the doped semiconductor is
a) 10 ^ 26 /m^3 b) 10 ^ 16 /m^3 c) 10 ^ 14 /m^3 d) 10 ^ 6 /m^3}


18.At room temperature, the diffusion and drift constants for holes in a P-type semiconductor were measured to be Dp = 10 cm^2/s and µp = 1200 cm^2/V-s, respectively. If the diffusion constant of electrons in an N-type semiconductor at the same temperature is Dn = 20 cm^2/s, the drift constant for electrons in it is
a) µn = 2400 cm^2/V-s b) µn = 1200 cm^2/V-s c) µn = 1000 cm^2/V-s d) µn = 600 cm^2/V-s


19.A common LED is made up of
a) intrinsic semiconductor b) direct semiconductor c) degenerate semiconductor d) indirect semiconductor


20.When operating as a voltage regulator, the breakdown in a Zener diode occurs due to the
a) tunneling effect b) avalanche breakdown c) impact ionization d) excess heating of the junction.

21.If the common base DC current gain of a BJT is 0.98, its common emitter DC current gain is
a) 51 b) 49 c) 1 d) 0.02


22.Negative resistance characteristics is exhibited by a
a) Zener diode b) Schottky diode c) photo diode d) Tunnel diode


23.Let En and Ep, respectively, represent the effective Fermi levels for electrons and holes during current conduction in a semiconductor. For lasing to occur in a P-N junction of band-gap energy 1.2 eV, (En - Ep) should be
a) greater than 1.2eV b) less than 1.2eV c) equal to 1.1eV d) equal to 0.7eV


24.In a P-well fabrication process, the substrate is
a) N-type semiconductor and is used to build P-channel MOSFET
b) P-type semiconductor and is used to build P-channel MOSFET
c) N-type semiconductor and is used to build N-channel MOSFET
d) P-type semiconductor and is used to build N-channel MOSFET


25.In a MOS capacitor with n-type silicon substrate, the Fermi potential ¢ = -0.41 V and the flat-band voltage Vfb = 0V. The value of the threshold voltage Vt is
a) -0.82 V b) -0.41 V c) 0.41 V d) 0.82


Refer given figure for question 26 and 27. Assume D1 and D2 to be ideal diodes.
26.Which one of the following statements is true?
a) Both D1 and D2 are ON.
b) Both D1 and D2 are OFF.
c) D1 is ON and D2 is OFF.
d) D2 is ON and D1 is OFF.


27.Values of Vo and I, respectively, are
a) 2V and 1.1 mA b) 0V and 0 mA c) -2V and 0.7 mA d) 4V and 1.3 mA


28.In a BJT CASCODE pair, a
a) common emitter follows a common base
b) common base follows a common collector
c) common collector follows a common base
d) common base follows a common emitter


29.Inside a 741 op-amp, the last functional block is a
a) differential amplifier b) level shifter c) class-A power amplifier d) class-AB power amplifier

30.For the MOSFET in the given circuit, the threshold voltage Vt = 0.5V, the process parameter KP = 150 µA/V^2 and W/L = 10. The values of Vd and Id, respectively, are
a) Vd = 4.5 V and Id = 1 mA
b) Vd = 4.5 V and Id = 0.5 mA
c) Vd = 4.8 V and Id = 0.4 mA
d) Vd = 6 V and Id = 0 mA
31.A negative feedback is applied to an amplifier with the feedback voltage proportional to the output current. This feedback increases the
a) input impedance of the amplifier b) output impedance of the amplifier c) distortion in the amplifier d) gain of the amplifier
32.The early effect in a BJT is modeled by the small signal parameter
a) r0 b) r∏ c) gm d) β
33.For a given filter order, which one of the following type of filters has the least amount of ripple both in pass-band and stop-band?
a) Chebyshev type I b) Bessel c) Chebyshev type II d) Elliptic
34.For a practical feedback circuit to have sustained oscillation, the most appropriate value of the loop gain T is
a) 1 b) -1 c) -1.02 d) 1.02
35.Assume the op-amps in given figure to be ideal. If the input signal vi is a sinusoid of 2V peak-to-peak and with zero DC component, the output signal vo is a
a) sine wave b) square wave c) pulse train d) triangular wave
36.In a common source amplifier, the mid-band voltage gain is 40 dB and the upper cutoff frequency is 150kHz. Assuming single pole approximation for the amplifier the unity gain frequency fT is
a) 6 MHz b) 15 MHz c) 150 MHz d) 1.5 GHz
37.An op-amp is ideal except for finite gain and CMRR. Given the open loop differential gain Ad=2000, CMRR = 1000, the input to the noninverting terminal is 5.002 V and the input to the inverting terminal is 4.999 V, the output voltage of the op-amp is

a) 14 V b) 24 V c) -6 V c) -8 V

38.The op-amp in the circuit in given figure has a non-zero DC offset. The steady state value of the output voltage Vo is
a) –RC dvs(t)/ dt b) – (1/RC)|vs(t)dt c) –V d) +V

39.For the circuit in given figure, if the value of the capacitor C is doubled, the duty-cycle of the output waveform Vo
a) increases by a factor of 2 b) increases by a factor of 1.44 c) remains constant d) decreases by a factor of 1.44

40.Assume the op-amp in the given circuit to be ideal. The value of the output voltage Vo is
a) 3.2 Vi b) 4 Vi c) 9 Vi d) 10 Vi

41.The complement of the Boolean expression F = (X + Y¯ + Z)(X¯ + Z¯)(X + Y) is
a) XYZ+XZ¯+Y¯Z b) X¯YZ¯+XZ+X¯Y¯ c) X¯YZ¯+XZ+YZ d) XYZ+X¯Y¯

42.The Boolean function F(A,B,C,D) = ∑(0,6,8,13,14) with don’t care conditions d(A,B,C,D) = ∑(2,4,10) can be simplified to
a) F = B¯D¯+CD¯+ABC¯ b) F = B¯D¯+CD¯+ABC¯D c) F = AB¯D¯+CD¯+ABC¯ d) F = B¯D¯+CD¯+ABCD

43.The Boolean function F = A¯D¯+B¯D can be realized by one of the following figures

44. For the multiplexer in given figure, the Boolean expression for the output Y is
a) A¯B¯+B¯C¯+AC b) AB¯+B¯C¯+AC¯ c) AB¯+B¯C+AC d) A¯B¯+B¯C+A¯C

45. Which one of the following is TRUE?
a) Both latch and flip-flop are edge triggered.
b) A latch is level triggered and a flip-flop is edge triggered.
c) A latch is edge triggered and a flip-flop is level triggered.
d) Both latch and flip-flop are level triggered.

46. In a schottky TTL gate, the Schottky diode
e) increases the propagation delay
f) increases the power consumption
g) prevents saturation of the output transistor
h) keeps the transistor in cutoff region

47. For which one of the following ultraviolet light is used to erase the stored contents
a) PROM b) EPROM c) EEPROM d) PLA

48. Which one of the following is NOT a synchronous counter
a) Johnson counter b) Ring counter c) Ripple counter d) Up-down counter

49. In 8085 microprocessor, the accumulator is a
a) 4 bit register b) 8 bit register c) 16 bit register d) 32 bit register
50. In the register indirect addressing mode of 8085 microprocessor, data is stored
a) at the address contained in the register pair
b) in the register pair
c) in the accumulator
d) in a fixed location of the memory

51. The output w[n] of the system shown in given figure is
a) x[n] b) x[n-1] c) x[n] – x[n-1] d) 0.5(x[n-1] + x[n])

52. Which one of the following is a periodic signal
a) x(t) = 2 e^j(t+(π/4)) b) x[n] = u[n] + u[-n] c) x[n] = ∑{∂[n-4k]-∂[n-1-4k]} where k = -∞to ∞ d) x(t) = e^ (-1+j)t

53. If the input-output relation of a system is y(t) = ∫x(t) dt where t = -∞ to 2t
a) linear, time-invariant and unstable
b) linear, non-causal and unstable
c) linear, causal and time invariant
d) non-causal, time invariant and unstable

54. Which one of the can be the magnitude of the transfer function | H(jw) | of a causal system

55. Consider the function H(jw) = H1(w) + jH2(w), where H1(w) is an odd function and H2(w) is an even function. The inverse Fourier transform of H(jw) is
a) a real and odd function
b) a complex function
c) a purely imaginary function
d) a purely imaginary and odd function

56. The laplace transform of given signal is
a) –A((1-e^cs)/s) b) A((1-e^cs)/s) c) A((1-e^-cs)/s) d) –A((1-e^-cs)/s)

57. If X(z) is the z-transform of x[n] = (1/2)^ |n|, the ROC of X(z) is
a) |z| > 2 b) |z| <>

58. In a linear phase system, τg the group delay and τp the phase delay are
a) constant and equal to each other b) τg is a constant and τp is proportional to w c) a constant and τg is proportional to w d) τg is proportional to w and τp is proportional to w

59. A signal m(t), band-limited to a maximum frequency of 20 kHz is sampled at a frequency fs kHz to generate s(t). An ideal low pass filter having cut-off frequency 37 kHz is used to reconstruct m(t) from s(t). The maximum value of fs required to reconstruct m(t) without distortion is
a) 20 kHz b) 40kHz c) 57 kHz d) 77 kHz

60. If the signal x(t) shown in given figure is fed to an LTI system having impulse response h(t) as shown in given figure, the value of the DC component present in the output y(t) is
a) 1 b) 2 c) 3 d) 4

61. The characteristic equation of an LTI system is given as s^3 + Ks^2 + 5s + 10. When the system is marginally stable, the value of K and the sustained oscillation frequency w, respectively, are
a) 2 and 5 b) 0.5 and √5 c) 0.5 and 5 d) 2 and √5

62. The time required for the response of a linear time-variant system to reach half the final value for the first time is
a) delay time b) peak time c) rise time d) decay time

63. The signal flow graph of the given network is

64. Let c(t) be the unit step response of a system with transfer function K(s+a)/(s+K). If c(0+)=2 and c(∞)=10, then the values of a and K, respectively, are
a) 2 and 10 b) -2 and 10 c) 10 and 2 d) 2 and -10

65. The loop transfer function of an LTI system is G(s)H(s)= K(s+1)(s+5) / s(s+2)(s+3). For K>0, the point on the real axis that DOES NOT belong to the root locus of the system is
a) -0.5 b) -2.5 c) -3.5 d) -5.5

66. The state space equation of the circuit shown in given figure for x1=v0, x2=I is

67. The open loop gain of a unity feedback system is G(s)=wn^2 / s(s+2wn). The unit step response c(t) of the system is

69. The angles of the asymptotes of the root loci of the equation s^3 + 5s^2 + (K+2)s + K = 0, for 0<=K<∞, are a) 0 and 270 b) 0 and 180 c) 90 and 270 d) 90 and 180 70. The bode plot corresponding to a proportional derivative controller is the one shown in given figure 71. In frequency modulation, the instantaneous a) amplitude of the carrier signal is varied with the instantaneous amplitude of the message signal b) amplitude of the carrier signal is varied with the instantaneous frequency of the message signal c) frequency of the carrier signal is varied with the instantaneous amplitude of the message signal d) frequency of the carrier signal is varied with the instantaneous frequency of the message signal 72. If X is a zero mean Gaussian random variable, then P{X<=0} is a) 0 b) 0.25 c) 0.5 d) 1 73. If a single-tone amplitude modulated signal at a modulation depth of 100% transmits a total power of 15W, the power in the carrier component is a) 5W b) 10W c) 12W d) 15W 74. In a superheterodyne receiver, rejection of the image signal can be achieved by using a a) higher local oscillatorn frequency b) crystal oscillator c) narrow band IF filter d) narrow band filter at RF stage 75. The number of bbits per sample of a PCM system depends upon the a) sampler type b) quantizer type c) number of levels of the quantizer d) sampling rate 76. Which one of the following is used for the detection of AM-DSB-SC signal a) Ratio detector b) Foster-Seeley discriminator c) Product demodulator d) Balanced-slpoe detector 77. Which one of the following signal pairs can represent a BPSK signal a) A cos2πfct, A sinπfct b) A cos2πfct, - A sinπfct c) - A cos2πfct, A sinπfct d) A sin2πfct, A cosπfct 78. Which one of the following can be used for the detection of the noncoherent BPSK signal a) matched filter b) phase-locked loop c) envelope detector d) product demodulator

79. Bits of duration Tb are to be transmitted using a BPSK modulation with a carrier of frequency Fc Hz. The power spectral density of the transmitted signal has the first null at the normalized frequency
a) |F – Fc|Tb = 0 b) |F – Fc|Tb = 1 c) |F – Fc|Tb = 2 d) |F – Fc|Tb = 4

80. The probability of bit error of a BPSK modulation scheme, with transmitted signal energy per bit Eb, in an additive white Gaussian noise channel having one-sided power spectral density N0, is
a) (1/2) erfc(Eb/2N0) b) (1/2) erfc√(Eb/2N0) c) (1/2) erfc(Eb/N0) d) (1/2) erfc√ (Eb/N0)

81. For a given transmitted pulse p(t), 0<=t<=T, the impulse response of a filter matched to the received signal is a) –p(t-T), 0<=t<=T b) –p(T-t), 0<=t<=T c) p(t-T), 0<=t<=T d) p(T-t), 0<=t<=T 82. The multiple access communication scheme in which each user is allocated the full available channel spectrum for a specified duration of time is known as a) CDMA b) FDMA c) TDMA d) MC-CDMA 83. GSM system uses TDMA with a) 32 users per channel b) 16 users per channel c) 8 users per channel d) 4 users per channel 84. If Rx(τ) is the auto-correlation function of a zero-mean wide-sense stationary random process X, then which one of the following is NOT true? a) Rx(τ) = Rx(-τ) b) Rx(τ) = -Rx(-τ) c) σx^2 = Rx(0) d) |Rx(τ)| <=Rx(0) 85. If E denotes the expectation operator, then E[X-EX]^3 of a random variable X is a) EX^3 – E^3X b) EX^3 + 2E^3X – 3EX Ex^2 c) 3EX^3 – E^3X d) 2EX^3 + E^3X – 3EX EX^2 86. A discrete memoryless source produces symbols m1,m2,m3 and m4 with probabilities 1/2, 1/4 , 1/8 and 1/8, respectively. The entropy of the source is a) ¼ b) 1 c) 7/4 d) 2 87. A channel has a signal-to-noise ratio of 63 and bandwidth of 1200 Hz. The maximum data rate that can be sent through the channel with arbitrary low probability of error is a) 600 bps b) 1200 bps c) 4800 bps d) 7200 bps 88. For the vectors A = X ax + Y ay and B = Z az, del . (A X B) is a) 0 b) 1 c) XZ d) YZ

89. Which one of the following relations represents Strokes’ theorem (symbols have their usual meaning)?
a) ∫s del X A.ds = 0 b) ∫L A.dl = ∫s del X A.ds c) ∫s A X dS = -∫v ( del X A)dv d) ∫v del.Adv = ∫s A.ds

90. Which one of the following relations is not correct (symbols have their usual meaning)?
a) del X E = - ∂B/∂t b) del X H = J + ∂E/∂t c) del.D = ρv d) del.B = 0

91. The electric field component of a uniform plane wave propagating in a lossless magnetic dielectric medium is given by E(t,z)=ax 5cos(10^9 t – 20/3 z)V/m. If η0 represents the intrinsic impedance of the free space, the corresponding magnetic field component is given by
a) H(t,z)= ay 5/2 η0 cos(10^9t – 20/3 z)A/m
b) H(t,z)= ay 10/ η0 cos(10^9t – 20/3 z)A/m
c) H(t,z)= az 5/2 η0 cos(10^9t – 20/3 z)A/m
d) H(t,z)= az 10/ η0 cos(10^9t – 20/3 z)A/m

92. The skin depth of a non-magnetic conducting material at 100 MHz is 0.15 mm. The distance which a plane wave of frequency 10 GHz travels in this material before its amplitude reduces by a factor of e^-1 is
a) 0.0015 mm b) 0.015 mm c) 0.15 mm d) 1.5 mm

93. A lossless transmission line has a characteristic impedance of 100 ohms and an inductance per unit length of 1 μH/m. If the line is operated at 1 GHz, the propagation constant β is
a) 2π rad/m b) 20π/3 rad/m c) 20π rad/m d) 2π *10^5 rad/m

94. When a load resistance Rl is connected to a lossless transmission line of characteristic impedance 75 ohms, it results in a VSWR of 2. The load resistance is
a) 100 ohms b) 75√2 ohms c) 120 ohms d) 150 ohms

95. A two-port network characterized by the S-parameter matrix, [S] = [0.3 L0 0.9 L90

0.9 L90 0.2 L0]

Is

a) both reciprocal and lossless b) reciprocal, but not lossless c) lossless, but not reciprocal d) neither reciprocal nor lossless

96. A lossless air filled rectangular waveguide has internal dimensions of a cm * b cm. If a=2b and the cutoff frequency of the TE02 mode is 12 GHz, the cutoff frequency of the dominant mode is
a) 1 GHz b) 3 GHz c) 6 GHz d) 9 GHz

97. A Hertzian dipole antenna is placed at the origin of a coordinate system and it is oriented along z-axis. In which one of the following planes the radiation pattern of the antenna has a circular shape?
a) x=0 b) y=0 c) z=0 d) ø=45

98. Which one of the following statements is not true?
a) Antenna losses are taken into account in calculating its power gain
b) For an antenna which does not dissipate any power, the directive gain and the power gain are equal
c) Directivity of an antenna is the maximum value of its directive gain
d) The directive gain of a Hertzian dipole is same in all direction

99. The directivity of a half dipole antenna is
a) 1.0 b) 1.5 c) 1.64 d) 2

100. Which one of the following is not true for a step index optical fibre?
a) It can support multiple modes
b) HE11 mode is its lowest order mode
c) The refractive index of the cladding is higher than that of the core
d) At a given wavelength, single mode operation is possible by proper choice of core diameter, core and cladding refractive indices.

GENERAL ABILITY TEST

101. Sarnath is situated in the state of
a) MP b) Bihar c) Punjab d) UP

102. Green house effect is due to the increase of atmospheric
a) CO2 level b) SO2 level c) CO level d) N2 level

103. In the month of July, it is winter in
a) New York b) Beijing c) Sydney d) London

104. The chairman of the Planning commission of India is
a) The prime minister b) The vice-president c) The union finance minister d) The union commerce minister

105. The satellite launch vehicle that placed a number of satellites ito orbit in May 2008 is
a) PSLV-C7 b) PSLV-C8 c) PSLV-C9 d) PSLV-C10

106.DRDO was formed in
a) 1947 b) 1950 c) 1954 d) 1958

107. SAMYUKTA is developed for the use of
a) Navy b) Army c) Air force d) RAC

108. DARL 202 is a variety of
a) pea b) garlic c) capsicum d) tomato

109. TRISHUL is
a) a surface to surface battlefield missile
b) a quick reaction surface to air missile
c) an intermediate range ballistic missile
d) a supersonic cruise missile

110. HUMSA is a
a) sonar b) tank c) mine d) night vision device

111. The value of 1+2i / 3-4i + 2-I / 5i , where i^2 is -1, is
a) -5/2 b) 5/2 c) 2/5 d) -2/5

112. The particular solution of the differential equation d^2y/dx^2 + 2 dy/dx + 5y = 0 satisfying the conditions y(0)=0 and y’(0)=1 is
a) y=1/2 e^-x cos2x b) y=1/2 e^-x sin4x c) y=1/2 e^-x sin2x d) y=1/2 e^-x cos4x

113. For the vectors A=3i-2j+k and B=2i-k, the value of (A*B).A is
a) 0 b) 1 c) 2 d) 3

114. The orthogonal trajectory of the family of curves x^2-y^2 = a (where a is a constant) and passing through the point (1,1) is
a) y=-1/x b) y=1/x c) y=-x d) y=x
115. The value of the line integral ∫ y^2 dx + 2xydy over the curve x=accost, y=asint is
a) 0 b) 1 c) 2 d) 4

116. The n-th partial sum of the infinite series 1/1*2 + 1/2*3 + 1/3*4+……1/n*(n+1)……..
a) 1/n+1 b) n+2/n+1 c) n/n+1 d) n-1/n+1

117. The complex-valued function f(z)=e^z is analytic for
a) no z b) all z c) real z only d) imaginary z only
118. The inverse of the matrix [ cos A sin A
-sin A cos A] is

a) [ -cos A Sin A b) [cos A sin A} c) [cos A -sin A d) [cos A -sin A
sin A cos A] sin A -cos A] -sin A cos A] sin A cos A]

119. Consider the function f(x) defined as
F(x) = 3x-1, x<0 x="0">0
In the following table, List I shows 4 expressions for limits of f(x) and List II indicates the values of the limits
List I List II
P.Lim x->2 f(x) 1. -1
Q.Lim x->0+ f(x) 2. 9
R.Lim x->0- f(x) 3. -10
S.Lim x->-3 f(x) 4. 5
The correct matches are
a) P-2,Q-4,R-1,S-3 B) P-2,Q-4,R-3,S-1 C) P-4,Q-2,R-1,S-3 D) P-4,Q-2,R-3,S-1

120. Two events A and B with probability 0.5 and 0.7, respectively, have joint probability of 0.4. The probability that neither A nor B happens is
a) 0.2 b) 0.4 c) 0.6 d) 0.8

121. Consider the differential equation
X^2 d^2/dx^2 + x dy/dx + (x^2 - 4)y = 0. The statement which is not true for it is
a) It is a linear second order ordinary differential equation
b) It can not be reduced to a differential equation with constant coefficients
c) X=0 is a regular singular point
d) It is a non-homogeneous second order ordinary differential equation

122. The sum of two numbers is 16 and the sum of their squares is a minimum. The two numbers are
a) 10,6 b) 9,7 c) 8,8 d) 5,11

123. The value of the definite integral 0∫(π/2)^(1/3) x^2 sin(x^3)dx is
a) -1/3 b) 0 c) 1 d) 1/3

124. A circle C2 is concentric with the circle C1 : x^2 + y^2 -4x +6y -12 =0 and has a radius twice that of C1. The equation of the circle C2 is
a) x^2 + y^2 -4x +6y -13 =0 b) x^2 + y^2 -4x +6y -87 =0 c) x^2 + y^2 -4x +6y -100 =0 d) x^2 + y^2 -4x +6y -88 =0

125. Consider the quadratic equation x^2 + px + q =0. If p and q are roots of the equation, the values of p and q are
a) p=0, q=0 only b) p=1, q=-2 only c) p=0, q=0 and p=1, q=-2 d) p=0, q=0 and p=-2, q=1

126. Consider the list of words: etiquette, accommodate, forty, exaggerate, continous, independent, receipt. The number of misspelt words are
a) 1 b) 2 c) 3 d) 4

127. Consider the following sentences
1. A few friends he has are all very rich.
2. Do not insult the weak.
3. The later of the two persons was more interesting.
4. All the informations were correct.
Out of these sentences, the grammatically correct sentence is
a) 1 b) 2 c) 3 d) 4

128. The appropriate auxiliary verb to fill in the blank of the sentence “Gandhi knew that he __ soon be jailed.”is
a) would b) will c) shall d) may

129. The number of missing punctuation marks in the sentence “Rajesh along with Amit went to the market.”is
a) 0 b) 1 c) 2 d) 3

130. The meaning of the word PLAGIARISM is
a) theft of public money b) theft of ideas c) belief in one god d) belief in many gods


132. ACROPHOBIA is the abnormal fear of
a) open spaces b) height c) fire d) water

133. The appropriate pair of prepositions to fill in the blank in the sentence “He was angry __ me, because my remarks were aimed __ him.”is
a) at,to b) with, at c) with, to d) at, for

134. The appropriate word(s) to fill up the blank in the sentence “ I remember __ voices in the middle of the night.”is (are)
a) hear b) to hear c) hearing d) heard

135. The passive voice form of the sentence “I have known him for a long time.”is
a) He is known to me for a long time.
b) He is known by me for a long time.
c) He has been known to me for a long time.
d) He has been known by me for a long time.

136. If kennel is to a dog, then __ is to a hen.
a) nest b) coop c) hole d) stable

137. If NATION is to 5236765, then NOTION is to
a) 573675 b) 563765 c) 576375 d) 557365

138. The next two numbers of the series 3,5,11,21 are
a) 34 and 52 b) 34 and 53 c) 35 and 52 d) 35 and 53

139. A, B and C are three places in India with longitudes 80E, 85 E and 90 E respectively. Which one of the following statements about the local times of the places is true?
a) Local time of C is ahead of that of B.
b) Local time of B is ahead of that of C.
c) Local time of A is ahead of that of C.
d) A, B and C all have the same local time.

140. In this question, notations +, / and * are used as follows
A + B means A is the husband of B.
A / B means A is the sister of B.
A * B means A is the son of B.
With these relations, the relationship
denoted by P / Q * R is
a) P is son of R
b) P is daughter of R
c) P is uncle of R
d) P is father of R

141. If DELHI is written as EDHIL, then PARIS is written as
a) APRIS b) SARIP c) SAPIR d) APISR

142. The number of prime numbers between 10 and 50 is
a) 10 b) 11 c) 12 d) 13

143. The odd one in the list : LAN, TCP/IP, HACKER and KILLER is
a) LAN b) TCP/IP c) KILLER d) HACKER

144. SAW is to carpenter as SCALPEL is to
a) surgeon b) mason c) plumber d) tailor

ANSWERS

1) d)Uttarpradesh
2) a) co2
3) c) sydney
4) a) prime minister
5) c) PSLV C9
6) d) 1958
7) b) army
8) don’t know
119) b) quick reaction surface to air missile
110) a) sonar
111 to 25 simple math problem
126) d) 4
127) might be sentence 2
128) b) will
129) c) 2
130) b) theft of ideas
131) c) permanent
132) b) height
133) b) with,at
134)b) to hear
135)d) he has been known by me for a long time
136) b) coop
137)a) 573675
138)d) 35,53
139)a) local time of C is ahead of that of B( not confirmed)
140) b) P is daughter of R
141) d) APISR
142) b) 11
143) c) killr
144) a) surgeon