BSNL Direct Recruitment of TTA Solved Paper 2013

Direct Recruitment Examination of TTA [tamilnadu Circle] July 2013

Max Marks 200 Time Allowed 3 Hours

I General Ability Test [20 Questions of each Mark]

II Basic Engineering [90 Questions of each Mark]

III Specialization [90 Questions of each Mark]

· Candidates have to answer all Questions

· There will be negative marking. For each wrong answer 25% of the mark of that question will be deducted.

11. The smallest number which when divided by 20,25,35 and 40 leaves remainders as of 14,19,29 and 34 respectively is:

a. 1394 b) 1404 c) 1664 d) 1406

22. Raju reads 3/5 of a book. He finds that there are still 80 pages left to be read. Total number of pages in the book are:

a. 100 b. 200 c. 300 4. 400

33. Indian cricket team won 4 more matches than it lost with Australia. If it won 3/5 of its matches, how many matches did India play?

a. 8 b. 12 c. 16 d. 20

44. A man pays 40 times the annual rent to purchase a building. The rate % per annum he derives from his investment is:

a. 25% b. 2.5% c. 4% d. 5%

55. The cost of 3 pens, 4 rulers and 5 erasers is Rs. 75 while that of 10 erasers, 6 pens and 7 rulers is Rs 138, find the cost of 3 pens, 1 ruler and 5 erasers.

a. Rs.39 b. Rs.42 c. Rs 44 d. Cannot be found

66. If a:b=3:7, find the value of (5a+b) : (4a+5b)

a. 15:44 b. 22:35 c. 15:49 d. 22:47

77. A can do a piece of work in 20 days and B in 30 days. A starts the work and worked for 6 days. Then B completed the remaining part of the work. In how many days was the work completed?

a. 24 b.27 c. 32 d. 34

88. A train covered a distance of 250 km, partly at an average speed of 40 km/hr and partly at 60 km/hr. Find the distance covered at 40 km/hr if it took 5 hours to cover the distance.

a. 150km b.120km c.100km d. cannot be found

99. For which of the following disciplines is Nobel Prize awarded?

a. Physical and Chemistry b. Physiology or Medicine c. Literature, Peace and Electronics d. All of the Above

110. Which is the least populated state in the Indian Union?

a. Arunachal Pradesh b. Goa C. Meghalaya d. Sikkim

111. The highest Indian decoration for showing valour and gallantry in the war is

a. Param Vishishta Seva Medal b. Ashoka Chakra C. Paramveer Chakra d. Mahaveer Chakra

112. Through which states does the river Chambal flow?

a. UP, MP and Rajasthan b. MP, Gujarat and UP c. Rajasthan, MP and Bihar d. Gujarat, Haryana and UP

113. Where is the Headquarters of World Trade Organization (WTO) situated?

a. Geneva b. Paris c. Washington DC d. Nairobi

114. What is the currency of China?

a. Yen b. Chinese Dollar c. Yuan d. Baht

15. Select the choice that provides the best meaning of the word “monetary”

a. Fiscal b. Stationary c. Scrupulous d. boring

16. Select the choice that provides the best meaning of the word “ Nascent”

a. Loyal b. treacherous c. unnamed d. incipient

17. Select the choice that provides the best meaning of the word “Chaste”

a. Curf b. Pure c. Outspoken d. loyal

18. Select the choice that provides the opposite meaning of the word “deter”

a. Encourage b. differ C. postpone d. prorogue

19. Select the most effective word from the choice to fill in the blanks to make the sentence meaningfully complete.

Ram agreed to ………………….. my orders

A. Carry away b. Carry on c. carry out d. carry off

20. Select the most effective word from choice to fill in the blanks to make the sentence meaningfully complete.

If a speech is full of pompous, it is ………………….

A. verbose b. grandiose c. bombastic d. grandiloquent

Part II

Which of the following is conserved when light waves interfere with each other?

Energy b. Intensity c. Amplitude d. Momentum

When n resistances each of value r are connected in parallel, then resultant resistance is x. When these n resistances are connected in series, total resistance is

nx b. rnx c. x/n d. n²x

Two bulbs marked 200 watt-250 volts and 100 watt-250 volts are joined in series to 250 volts supply. Power consumed in circuit is

33 watt b.67watt c. 100 watt d. 300 watt

Which of the following capacitors is polarized?

Mica b. Ceramic c. Plastic film d. Electrolytic

A 4.7 M W resistor is in series with a 0.015 mF capacitor. The combination is across a 12 V source. How long does it take the capacitor to fully charge?

35 ms b. 352 ms c. 3.5s d. 70.5 ms

A sine wave voltage is applied across a capacitor. When the frequency of the voltage is decreased, the current

Increases b. remains constant c. Decreases d. ceases

Three 10 KW resistors are connected in series. A 20kW resistor is connected in parallel across one of the 10kW resistors. The voltage source is 24 V. the total current in the circuit is

900 mA b. 9mA c. 90 mA d. 800 mA

A certain circuit is composed of two parallel resistors. The total resistance is 1,403W. One of the resistors is 2W. The other resistor value is

A. 1,403W b. 4.7 kW c. 2 kW d. 3,403 W

A 33W half-watt resistor and a 330W half-watt resistor are connected across a 12 V source. Which one(s) will overheat?

33W b. 330W c. both resistors d. neither resistor

A certain appliance uses 350 w. If it is allowed to run continuously for 24 days, how many kilowatt-hours of energy does it consume?

20.16 kWh b. 201.6 kWh c. 2.01kWh d. 8.4 kWh

A Power supply produces a 0.6 W output with an input of 0.7 W . Its percentage of efficiency is

8.57% b. 42.85% c. 4.28% d. 85.7%

A 6V battery is connected to a 300W load. Under these conditions, it is rated at 40 Ah. How long can it supply current to the load?

1 hr b. 200 hrs c. 2000 hrs d. 10 hrs

Doppler shift in frequency does not depend on

The speed of the observer
The speed of the source
The relative speed of the observer with respect to source
The distance between the source and the observer

The amplitude of light wave at a distance x is A. At a point distant 3x from the source, the amplitude would be

9A b. 3A c. A/3 d. A/9

Korchoff’s laws are not applicable to circuits with

Distributed parameters
lumped parameters
passive elements
non-linear resistances

Cells are connected in series in order to increase

Current capacity
Life of the cells
Voltage rating
Terminal voltage

In lead acid batteries

The electrolyte is weak sulphuric acid
The number of plates is always odd
The number of negative plates is one more than the number of positive plates
All of the above

The rating of fuse wire is always expressed in

Volts b. amperes c. ampere volts d. ampere hours

The thickness of insulation provided on the conductor depends upon

Current rating b. voltage rating c. both A. and B. d. none of these

When two cells are connected in parallel, it should be ensured that they have

Identical internal resistances b. equal emfs c. same make d. same ampere-hour capacity

Which cannot be calculated using the principle of conservation of energy?

The energy of a proton at rest
The production of back emf in a motor
Voltage transformation in an ideal transformer
The escape velocity of an object from the gravitational field of a planet

Why does superconductivity acquire in certain materials at low temperatures

At low temperatures there are no lattice vibrations
Some pairs of electrons experience net attractions at low temperatures
The materials allow loose resistance at low temperatures
At low temperatures the materials become magnetic and this reduces the scattering of electron pairs

Specific resistance is measured in

Mho b. ohm c. ohm-cm d. ohm/cm

The equation of alternating current is i=42.4 sin 628t. Then the average value of current is

42.42A b. 27A c. 38A d. 22A

Which of the following case represents the largest mmf?

A 20 turn coil wound around a 10cm iron core and passing a current of 3A
A 60 turn coil wound a 10cm iron core and passing a current of 1 A
A 100 turn coil wound a 10cm iron core and passing a current of 0.75A
A 50 turn coil wound a 10cm iron core and passing a current of 0.75A

The slope of line perpendicular to 2x+y=0 is

½ b. -1/2 c. 2 d. -2

The line passing through (2,3) and (3,2) is

X+y-5=0 b. x-y-1=0 c. x+y+1=0 d. x-y+1=0

Equation of circle passing through origin and center(a,0) on x axis with radius ‘a’ is

(x-a)²+ y2 =a² b. x²-y²-2ax=0 c. both A and B d. neither of above

The angle made by the line x-y+5 =0 with y-axis is

30 degree b. 45 degree c. 60 degree d. 150 degree

The angle covered by a wheel in 3 sec, if it makes 200 revolutions in a minute, is

10π b. 15 π c. 20 π d. 30 π

If Ѳ=45⁰ =, then sec Ѳ cot Ѳ – cosec Ѳ tan Ѳ =

0 b. 2 c. √2 d. 2√2

Which of the following is not an example of a vector?

Displacement b. Momentum c. Mass d. Angular velocity

The sum of two unit vectors is a unit vector. The magnitude of their difference is

2 b. √3 c. √2 d. 1

Rank of the matrix 1 -2 3 is

2 4 1

1 2 7

a) 1 b) 2 c) 3 d) none of these

35. Matrix A = cos Ѳ -sin Ѳ is

Sin Ѳ cos Ѳ

a) orthogonal matrix b) reciprocal matrix c) transposed matrix d) second order non-linear

36. Differential equation d2y / dx2 + sinx dy/dx + ye^x = sinhx is

A. First order and linear

B. First order and non-linear

C. Second order linear

D. Second order non-linear

37. Which of the following equations has the same graph as the line 3y-1.5 x = 0?

A. Y=x/3 B. y=2x+3 C. y=2x D. y=x/2

38. If y=x^x, x > 0, then dy/dx is

A. log x B. 2+log x C. X ^x log x D. X ^x (1+log x)

39. d/dx (cos ^-1 x + sin ^-1 x) is equal to

A. π/2 B. 0 C. 2 π D. None of these

40. If √x + √y = 4 then dx/dy at y=1 is

A. 3 B. -1 C. -3 D. none of these

^π/2

41. ∫ ₀ sin 4 Ѳ / sin Ѳ d Ѳ is equal to

A. 2/3 B. 8/3 C. ¾ D. 4/3

42. The value of ∫ ₀ (x -1) |x-1| dx is equal to

A.-2/3 B. 4/3 C. 2/3 D. 0

43. If ω is a cube root of unity, then value of (1+ ω- ω²) (1- ω+ ω²) is

A. 1 B. 0 C. 2 D. 4

44. The locus represented by | Z-1| = |Z+ i | = is

A. Circle of radius 1 B. an ellipse with foci at (1,0) and (0,1)

C. a straight line through the origin D. a circle on the line joining (1,0), (0,1) as diameter

45. If z is a complex number, then

A. |Z²| > |Z|² B. . |Z²|=. |Z|² C. |Z²| < . |Z|² D. none of these

46. Value of √I + √-I is

A.0 B. +/- √2 C. –i √2 D. (-2+2i)

47. What is the most significant development in electronics since World war II ?

A. The development of LCD TV B. The Development of the diode

C. The Development of the transistor D.The development of TRIAC

48. Which material may also be considered a semiconductor element?

A. Carbon B. Ceramic C. Mica D. Argon

49. What can a semiconductor sense?

A. Temperature B. Magnetism C. Pressure D. All of these

50. The diffusion potential across a p-n junction

A. Decreases with increasing doping concentration

B. Increases with decreasing band gap

C. Does not depend on doping concentrations

D. Increases with increase in doping concentrations

51. Forward bias of a silicon P-N junction will produce a barrier voltage of approximately how many volts?

A. 0.2 B. 0.3 C. 0.7 D. 0.8

52. A P-N junction mimics a closed switch when it

A. has a low junction resistance B. is reversed biased

C. Cannot overcome its barrier voltage D. Has a vide depletion region

53. If conductance increases as temperature increases, this is known as a

A. Positive coefficient B. Negative current flow C. Negative coefficient

D. positive resistance

54. Which statement best describes an insulator?

A. a material with many free electrons B. a material doped to have some free electrons C. A Material with few free electrons D. none of the above

55. What electrical characteristic of intrinsic semiconductor material is controlled by

The addition of impurities?

A. Conductivity B. Resistance C. Power D. All of the above

56. A JFET

A. Is a current controlled device B. Has a low input resistance

C. Is a Voltage controlled device D. Is always forward biased

57. When transistors are used in digital circuits they usually operate in the:

A. Active region B. Breakdown region

C. Saturation and Cut off regions D. Linear region

58. A current ratio of I_C/I_Eis usually less than one and is called:

A. beta B. theta C. Alpha D. Omega

59. In a C-E configuration, an emitter resistor is used for:

A. Stabilization B. ac signal bypass

C. Collector bias D. higher gain

60. A transistor may be used as a switching device or as a:

a) Fixed resistor b) tuning device c) rectifier d) variable register

61. In a class B Push-Pull amplifier, the transistors are biased slightly above the cutoff to avoid

a) Crossover distortion b) Unusually high efficiency c) Negative feedback

d) A low input impedance

62. Often a common – collector will be the last stage before the load: the main function of this stage is to

a) Provide voltage gain b) Buffer the voltage amplifiers from the low-resistance loads c) Provide phase inversion

d) Provide a high frequency path to improve the frequency response

63. The center frequency of a band pass filter is always equal to the

a) Bandwidth b) -3dB Frequency

c) Bandwidth divided by Q d) Geometric average of the critical frequencies

64. In an averaging amplifier, the input resistances are

a) Equal to the feedback resistance b) Less than the feedback resistance

c) Greater than the feedback resistance d) Unequal

65. The ramp voltage at the output of an op-amp integrator

a) increase or decreases at a linear rate b) increases or decreases at an exponential rate

c) Is always increasing and never decreasing d) is constant

66. What is the minimum frequency at which a crystal will oscillate?

a) Seventh harmonic b) third harmonic c) fundamental d) second harmonic

67. Sinusoidal oscillators operate with

a) Positive feedback b) negative feedback

c) Both positive and negative feedback d) none

68. Avalanche photodiodes are preferred over PIN diodes in optical communication

Systems because of

a) Speed of operation b) higher sensitivity

c) Larger bandwidth d) larger power handling capacity

69. Very Large Scale Integration (VLSI)

A) Refers to a small computer on a chip b) cannot be applied to MOS systems

c) Refers to IC’s with complexity below 100 gates d) does not require costly process facilities

70. Avalanche breakdown results basically due to

a) Impact ionization b) strong electric field across the junction

c) Emission of electrons d) rise in temperatures

71. An ideal power supply has

a) Zero internal resistance b) very large input resistance

c) Very large output resistance d) very low output resistance

72. Higher order active filters used for variable

a) Bandwidth b) gain in the pass band c) impedence d) roll-off rate

73. Convert the octal number 17 to decimal

a) 22 b) 23 c) 15 d) 34

74. How many binary digits are required to count to 100 ₁₀ ?

a) 5 b) 8 c) 7 d) 9

75. A logic circuit that provides a HIGH output for both inputs HIGH or both inputs LOW is

a) An EX-NOR gate b) an OR gate c) an EX-OR gate d) a NAND gate

76. Parity systems are defined as either _________ or ___________ and will add an extra _______to the digital information being transmitted

a) Positive, negative, byte b) odd, even, bit

c) Upper, lower, digit d) on, off, decimal

77. One of De Morgan’s theorems states that X+Y = XY Simply stated, this means that logically there is no difference between

a. a NOR and an AND gate with inverted inputs

b. a NAND and OR gate with inverted inputs

c. an AND and a NOR gate with inverted inputs

d. a NOR and a NAND gate with inverted inputs

78. How many gates would be required to implement the following Boolean expression before?

Simplification? XY + (X+Z) + Y ( X+Z)

a) 3 b) 4 c) 5 d) 6

79. Use Boolean algebra to find the most simplified SOP expression for

F=ABD+ CD + ACD + ABC + ABCD

a) F=ABD+ABC+CD b) F=CD+AD c) F=BC+AB d) F=AC+AD

80. The implementation of simplified sum-of-products expressions may be easily implemented into actual logic circuits using all Universal ________gates with little or no increase in circuit

Complexity. (Select the response for the blank space that will BEST make the statement true)

a) AND/OR b) NAND c) NOR d) OR/AND

81. A logic probe is placed on the output of a gate and the display indicator is dim. A pulser is used on each of the input terminals, but the output indication does not change. What is wrong?

a. The output of the GATE appears to be open

b. The dim indication on the logic probe indicates that the supply voltage is probably low

c. The dim indication is a result of a bad ground connection on the logic probe

d. The gate may be a tristate device.

82. How is a J-K flip-flop made to toggle?

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

83. On a master – slave flip-flop, when is the master enabled?

a) When the gate is LOW b) When the gate is HIGH

c) Both of the above d) neither of the above

84. How can parallel data be taken out of a shift register simultaneously?

a) Use the Q output of the first FF b) Use the Q output of the last FF

c) The all of the Q outputs together d) Use the Q output of each FF

85. Synchronous counters eliminate the delay problems encountered with asynchronous counters

Because the:

a. Input clock pulses are applied only to the first and last stages

b. Input clock pulses are applied only to the last stage

c. Input clock pulses are not used to activate any of the counter stage

d. Input clock pulses are applied simultaneously to each stage

86. The check sum method of testing a ROM :

a) Indicates if the data in more than one memory location is incorrect

b) Provides a means for locating and correcting data errors in specific memory locations

c) Allows data errors to be pinpointed to a specific memory location

d) Simply indicates that the contents of the ROM are incorrect

87. Which of the following consumes minimum power?

a) TTL b) CMOS c) DTL d) RTL

88. How many select lines will a 31:1 multiplexer have?

a) 5 b) 8 c) 9 d) 11

89. Karnaugh map is use for the purpose of

a) reducing the electronic circuits used

b) to map the given Boolean logic function

c) to minimize the terms in a Boolean expression

d) to Maximize the terms in a Boolean expression

90. Which of following requires refreshing?

a) SRAM b) DRAM c) ROM d) EPROM

Part III

Wheatstone bridge method of resistance measurement is ideally suitable for the measurement of resistance values in the range

0.001 ohm to 1 ohm B. 0.1 ohm to 100 ohm c. 100 ohm to 10 k-ohm d. 100 k-ohm to 10 M ohm

The value of resistance of an earthing electrode depends upon

Shape and material of electrode b. depth to which electrode is driven into earth c. specific resistance of soil D. All of the above

A dc motor can be easily identified by

Yoke b. Size of the conductor c. Commutator d. Winding

In a dc motor, the ratio of back emf to supply emf is an indication of its

Efficiency b. speed regulation c. starting torque d. running torque

In case of Parallel operation of compound generators, for proper division of load from no load to full load, it is essential that

The regulation of each armature should be same
their series field resistances should be equal
their ratings should be equal
none of these

The frequency of voltage generated in an alternator depends on

Number of poles b. speed of alternator c. both A. and B. d. type of winding

A 20 pole alternator rotates at 600 rpm. The periodic time of current in seconds per cycle is

A. 0.02 B. 0.01 C.0.005 D. 0.04

When an induction motor runs at rated load and speed, the iron losses are

Negligible b. very heavy c. independent of supply frequency d. independent of supply voltage

In a three-phase system, the voltages are separated by

45 degree B. 90 degree C. 120 degree D. 180 degree

The equation of a current given by i=I_m sin 2ωt. the frequency of the current in Hz is

ω/2π 2. ω/2 c. 2ω/π d. ω/π

In a ∆ - connected source feeding a Y-connected load

Each phase voltage equals the difference of the corresponding load voltages
Each phase voltage equals the corresponding load voltage
Each phase voltage is one-third the corresponding load voltage
Each phase voltage is 60⁰ out of phase with the corresponding load voltage

A single – phase sinusoidal voltage of 120 V is connected to a 90Ω load. Current in the circuit is

13.3 mA b. 133 mA c. 1.33 A d. 1.33 mA

The primary winding of a transformer has 110 V ac across it. What is the secondary voltage if the turns ratio is 8?

8.8 V b. 88V c. 880V d. 8888V

Slip of induction motor does not depends on

Rotor speed b. synchronous speed c. shaft torque d. core loss

In a synchronous motor, the inverted curve represent the relation between

Field current & Armature current b. Armature current and Power Factor c. Field current & Power Factor d. none of these

In a transformer the coils of primary and secondary are placed concentrically to achieve

Reduced leakage flux between primary and secondary winding
Reduced copper losses in the winding
Reduced insulation cost of the windings
Reduced voltage per turn in the winding

What is the necessity of copper brushes in a dc motors?

To absorb the mechanical shocks produced during running condition
To convert alternating supply current to direct current
To increase the flux cutting by the rotor
None of these

Bulk oil circuit breaker is suitable for voltages up to

4 kV b. 10 kV c. 25 kV d. 36 kV

Shunt reactors are connected with transmission lines for

Limiting fault current b. limiting fault voltage c. absorbing reactive power d. absorbing high voltage surges

The advantage of grounding a power system is that

Earth fault current can be used to operate relays
“Arching ground” phenomenon is avoided
It provides symmetry to the line impedances
Both A) and B)

The SCR is turned-off when the anode current falls below

Forward current rating b. break over voltage c. holding current d. latching current

Chopper control for DC motor provides vibration in

Input voltage b. Frequency c. both A and B d. none of these

As per sampling theorem

The signal should be sampled at least twice each cycle of its lowest frequency
Twice each cycle of its highest frequency
Guard time should be as large as possible
Nyquist rate should as low as possible

In communication, the sampling technique leads to

Higher efficiency b. higher speed of communication c. cheaper communication d. all of the above

In frequency modulation, if the frequency of the modulating voltage is doubled, the rate of deviation of carrier frequency

Doubles b. becomes four times c. becomes half d. remains unaltered

The drawback of FM relative to AM is that

Noise is very high for high modulation frequencies
Larger bandwidth is required
Higher modulating power is required
Higher output power is required

In pulse modulation system, the modulating signal controls the

Pulse amplitude b. pulse width c. pulse spacing d. al of these

A PLL can be used to demodulate

PAM signals b. PCM Signals c. FM Signals d. DSB-SC Signals

Modems are used for data transmission over telephone lines to

Increase the transmission capacity b. improve noise performance c. incorporate error control handling d. eliminate dc component in the transmitted signal

In a DM(Delta Modulation ) system, the granular (idling) noise occurs when the

Modulation signal increases rapidly b. pulse rate decreases c. modulating signal remains constant d. pulse amplitude decreases

PCM systems require regenerative repeaters over long distances. The correct sequence of the operations which such a repeater performs is

Timing, equalization and decision making
Equalization, timing and decision making
Timing, thresholding (decision) and equalization
Thresholding, timing and equalization

The loading of telephone lines by inductances at uniform intervals is done to

Reduce attenuation b. eliminate high frequencies c. reduce near end cross talk d. reduce far end cross talk

Telephone traffic is specified in terms of

Average waiting time b. peak waiting time c. grade of service d. Erlongs

Which of the following requires a synchronizing signal?

Single channel PPM system b. PAM c. PDM d. all of these

In a PCM system, the number of quantization levels are 16 and the maximum signal frequency is 4 KHz, the bit transmission rate is

64 K bits/sec b. 16 K bits/sec c. 32 K bits/sec d. 32 bits/sec

PAM signals can be demodulated by using a

Low pass filter(LPF) alone b. a Schmitt trigger followed by a LPF c. a differentiator followed by a LPF d. a clipper circuit followed by a LPF

Microwave frequency range extends from

3 MHz to 30 MHz b. 30 MHz c. 300 MHz to 300 GHz d. 300 MHz to 3000MHz

Which of the following noise becomes important at microwave frequencies?

Short noise b. Flicker noise c. thermal noise d. transmit time noise

The advantage of microwave lower frequency signals are

Increased bandwidth b. ability to use high gain, directive antenna c. greater secrecy d. all of these

When the free space wave length of a signal equals the cut-off wavelength of guide

Group velocity of the signal becomes zero
Phase velocity of the signal becomes infinite
Wavelength within the waveguide becomes infinite
All of above

When microwave signals follow the curvature of the earth, this is called

Ducting b. Farady effect c. tropospheric scatter d. ionospheric reflection

The wavelength of microwaves at 100 GHz will be

3 cm b. 3 mm c. 0.03 cm d. 0.3 m

Klystron oscillator may be used as

Signal source in microwave generator b. local oscillator in microwave receiver c. pump oscillator in parametric amplifier d. all of these

TWT is basically a/an

Oscillator b. Tuned Amplifier c. wideband amplifier d. audio amplifier

What is the main difference between synchronous and asynchronous transmission

The bandwidth required is different
The pulse height is different
The clocking is derived from the data in synchronous transmission
The clocking is mixed with data in asynchronous transmission

Satellite transponders

Use a higher frequency for reception of radiation from earth stations and lower frequency for transmission to earth stations
Use lower frequency for reception of radiation from earth stations and higher frequency for transmission to earth stations
Use a single frequency for reception and transmission from one point on earth to another
Are devices that echos the radiation without change from oen point on earth to another

What function does a serial interface perform in data communication?

Converts serial data into audio data signals
Converts analog signal into digital signal
Converts parallel data into a stream bites and vice-versa
All of these

The data rate of the ISDN Basic Rate Access D Channel is

64 Kbps b. 16 Kbps c. 8 Kbps d. 144 Kbps

In a prototype low pass filter, the series and shunt elements are respectively

Capacitive and inductive b. inductive and capacitive c. capacitive and resistive d. resistive and inductive

Mho relay is normally used for the protection of

Long transmission lines b. medium length lines c. short length lines d. no length criterion

The leakage resistance of a 50 km long cable is 1 MΩ. For a 100Km long cable it will be

1M Ω b. 2 M Ω c. 0.66M Ω d. none of these

The effect of bonding the cable is to

Increase the effective resistance and inductance
Increase the effective resistance but reduce inductance
Decrease the effective resistance and inductance
Decrease the effective resistance but increase the inductance

The main advantage of ac transmission over dc transmission system is

Less insulation problems
Low losses in transmission power over long distances
Less instability problems
More economic as end use appliances are mostly AC powered

Constant voltage transmission has the advantage(s) of

Availability of steady voltage at all loads at the receiving end
Possibility of better protection for the line due to possible use of higher terminal reactance
Possibility of carrying increased power for a given conductor size in case of long distance heavy power transmission
All of these

For a distortion less transmission line where G is the shunt conductance between two conductors.

RL=GC b. RC=GL c. RG=LC d. RLGC=0

Which of the following statement is not correct?

It is not possible to have precise measurement which are not accurate
Correctness in measurement requires both accuracy and precision
Reproducibility and consistency are expressions that best describe precision in measurements
An instrument with 2% accuracy is better than another with 5% accuracy

A wattmeter has a full scale range of 2500 W. It has an error ±1% of true value. If true power is 1250 W , range of reading will be

1225 W – 1275 W b. 1245 W – 1255 W c. 1200 W – 1300 W d. 1237.5 W – 1262.5 W

If two 300 V full-scale voltmeters V1 & V2 having sensitivities of 100 k Ω / v and 150 k Ω/v are connected in series to measure 500 V then

V1 and V2 will read 250 V each b. V1 will read 200V and V2 will read 300 V c. V1 will read 300 V and V2 will read 200 V d. V1 and V2 will read 0

Hysteresis in an instrument means

Repeatability of the instrument
Reliability of the instrument
Change in same reading when input is first increased and then decreased
Inaccuracy due to change in temperature

A digital volt meter measures

Peak value b. peak-to-peak value c. rms value d. average value

In a digital voltmeter, the Oscillator frequency is 400 kHz and ramp voltage falls from 8 V to 0 V in 20msec. The number of pulses counted by the counter is

800 b. 2000 c. 4000 d. 8000

Digital instruments have input impedance of the order of

1 Ω B. k Ω C. M Ω D. m Ω

Q-factor of Q-Meter is

ω₀ R/L b. LR/ ω_{0 c.}ω₀L/R d. none of these

Range of an analog transducer is 0-10 V. For a resolution of 5 mV, the bits of ADC will be

8 b. 9 c. 10 d. 11

Backlash is

Unwanted signal tending to obscure the transducer signal
Maximum angle or distance through which any part of mechanical system may be moved in one direction without causing motion of the next part
Departure of instrument output from its calibrated value
All of these

In a closed loop control system

Control action depends on the output and also on the input command
Output signal is feedback to be compared with reference signal
Accuracy is better than in open loop system
All of these

A servo system must have

Feedback system b. power amplifier to amplify error c. capacity to control position or its derivative d. All of these

The main drawback of a feedback system is

Inaccuracy b. inefficiency c. insensitivity d. instability

In a second order system, if the damping factor ε is less than unity , the system will be

Under damped b. over damped c. critically damped d. freely oscillating

The most suitable method for determining the stability and transient response of a system is

Bode plot b. Root locus c. Nyquist criterion d. Routh Hurwitz criterion

For Type three system , the lowest frequency asymptote will have the slope of

-20dB/octave b. -6 dB/octave c. -12 dB/octave d. -18 dB/octave

Excessive noise in a control system may result in

Reduction in gain b. reduction in bandwidth c. oscillations d. saturation in amplifying stages

A system with gain margin close to unity or a phase margin close to zero is

Highly stable b. Highly oscillatory c. relatively stable d. none of these

How many address lines are needed to address each memory location in a 2048 X 4 memory chip?

10 b. 11 c. 12 d. 18

The bus which is used to transfer data from main memory to peripheral device is the

Data bus b. Input bus c. DMA bus d. Output bus

RISC is characterized by

Hardware Control design with no micro codes
Fixed instruction format
Several general purpose registers and large cache memories which support very fast access of data d. All of the above

The microprocessor contains ROM chip which contains

Control Function b. Arithmetic Functions c. Instructions to execute data d. Memory Functions

An assembler for a microprocessor is used for

Assembly of processors in a production line
Creation of new programs using different modules
Translation of a program from assembly language to machine language
Translation of a higher level language into English text.

A Language developed to assist children in learning geometric shapes and computing is

COBOL b. BASIC c. LOGO d. LISP

The process of accessing data stored in a tape is similar to manipulating data on

Stack b. Queue c. List d. heap

Which of the following chips can be reprogrammed with special electric pulses?

EPROM b. PROM c. ROM d. EEPROM

A computer program that translates one program instruction at a time into machine language is called

Interpreter b. CPU c. compiler d. Simulator

Which of the following memories has the shortest access time?

Cache Memory b. Magnetic Bubble Memory c. Magnetic Core Memory d. RAM

Linkage between the CPU and users is provided by

Peripheral Devices b. Storage c. Control Unit d. Software

Which of following typically uses a keyboard for input

Desktop Terminal b. Point of Sale terminal c. Financial Transaction terminal D. All of these

How many OSI layers are covered in the X.25 standard?

Three b. Four c. Two d. Seven

Layer Four of the OSI model is

Physical layer b. Link layer c. Transport Layer d. Network Layer

The TCP/IP protocol which is used for remote terminal connection service is

TELNET b. FTP c. RARP d. UDP

Which of the Following protocol is used for transferring files from one machine to another?

RARP b. ARP c. TCP D. FTP

A transparent DBMS

Cannot hide sensitive information from users
Keeps its logical structure hidden from users
Keeps its physical structure hidden from users
Both B) and C) above

P.DHAKSHNAMOORTHY DEEE., BE.,

dhakshna.jp@gmail.com

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BSNL Direct Recruitment of TTA Solved Paper 2013

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