BSNL TTA EXAM PAPERS ALL IN ONE
BSNL TTA Question Paper-Instruments
and Measurement Specialization 2007
(1) Instrument is a device
for determining
(a) the magnitude of a
quantity
(b) the physics of a
variable
(c) either of the above
(d) both (a) and (b)
(2) Electronic instruments
are preferred because they have
(a) no indicating part
(b) low resistance in
parallel circuit
(c) very fast response
(d) high resistance in
series circuit
(e) no passive elements.
(3) A DC wattmeter
essentially consist of
(a) two ammeters
(b) two voltmeters
(c) a voltmeter and an
ammeter
(d) a current and potential
transformer
(4) Decibel is a unit of
(a) power
(b) impedance
(c) frequency
(d) power ratio
(5) A dc voltmeter may be
used directly to measure
(a) frequency
(b) polarity
(c) power factor
(d)power
(6) An accurate voltmeter
must have an internal impedance of
(a) very low value
(b) low value
(c) medium value
(d) very high value
(7) The insulation
resistance of a transformer winding can be easily measured with
(a) Wheatstone bridge
(b) megger
(c) Kelvin bridge
(d) voltmeter
(8) A 100 V voltmeter has
full-scale accuracy of 5%. At its reading of 50 V it will give an error of
(a) 10%
(b) 5%
(c) 2.5%
(d) 1.25%
(9) You are required to
check the p. f. of an electric load. No p.f. meter is available. You would
use:
(a) a wattmeter
(b) a ammeter, a voltmeter
and a wattmeter
(c) a voltmeter and a
ammeter
(d) a kWh meter
(10) The resistance of a
field coil may be correctly measured by using
(a) a voltmeter and an
ammeter
(b) Schering bridge
(c) a Kelvin double bridge
(d) a Maxwell bridge
(11) An analog instrument
has output
(a) Pulsating in nature
(b) Sinusoidal in nature
(c) Which is continuous
function of time and bears a constant relation to its input
(d) Independent of the input
quantity
(12) Basic charge measuring
instrument is
(a) Duddel's oscillograph
(b) Cathode ray oscillograph
(c) Vibration Galvanometer
(d) Bailastic Galvanometer
(e) Battery Charging
equipment
(13) A.C. voltage can be
measured (using a d.c. instrument) as a value obtained
(a) by subtracting the d.c.
reading from it's a.c. reading.
(b) Using the output
function of the multimeter
(c) By using a suitable
inductor in series with it
(d) By using a parallel
capacitor with it
(e) None of the above
(14) A moving coil permanent
magnet ammeter can be used to measure
(a) D. C. current only
(b) A. C. current only
(c) A. C. and D. C. currents
(d) voltage by incorporating
a shunt resistance
(e) none of these
(15) Select the wrong
statement
(a) the internal resistance
of the voltmeter must be high
(b) the internal resistance
of ammeter must be low
(c) the poor overload
capacity is the main disadvantage of hot wires instrument
(d) the check continuity
with multimeter, the highest range should be used.
(e) In moving iron
voltmeter, frequency compensation is achieved by connecting a capacitor across
its
fixed coil.
(16) Which of the following
instrument is suitable for measuring both a.c. and d.c.
quantities.
(a) permanent magnet moving
coil ammeter.
(b) Induction type ammeter.
(c) Quadrant electrometer.
(d) Moving iron repulsion
type ammeter.
(e) Moving iron attraction
type voltmeter.
(17) Swamping resistance is
used in moving coil instruments to reduce error due to
(a) thermal EMF
(b) temperature
(c) power taken by the
instrument
(d) galvanometer sensitivity.
(18) A power factor meter is
based on the principle of
(a) electrostatic instrument
(b) Electrodynamometer
instrument
(c) Electro thermo type
instrument
(d) Rectifier type
instrument.
(19) A potentiometer
recorder is used for
(a) AC singles
(b) DC signals
(c) both (a) and (b)
(d) time varying signals
(e) none of these.
(20) Transformers used in
conjunction with measuring instruments for measuring purposes are
called
(a) Measuring transformers
(b) transformer meters
(c) power transformers
(d) instrument transformers
(e) pulse transformers.
(21) Leakage flux in an
electrical machine is measure by
(a) Ballistic galvanometer
(b) Flux meter
(c) Either (a) or (b)
(d) Vibration galvanometer
(e) CRO
(22) A C.R.O. is used to
indicate
(a) supply waveform
(b) magnitude of the applied
voltage
(c) B.H. loop
(d) all of these
(e) Magnitude of the current
flowing in it.
(23) An oscillator is a
(a) an amplifier having
feedback network
(b) a high gain amplifier
(c) a wide band amplifier
(d) a untuned amplifier
(e) None of these
(24) Distortion can be
measured by
(a) Wave meter
(b) Digital filters
(c) Wein bridge circuit
(d) Bridge T filter circuit
(25) Series connected Q-
meter is preferable for measurement of components having
(a) high impedance
(b) low impedance
(c) both (a) and (b)
(d) high frequency
(e) low capacitance
(26) A potentiometer is
(a) an active transducer
(b) a passive transducer
(c) a secondary transducer
(d) a digital transducer
(e) a current sensing
transducer
(27) The basic components of
a digital voltmeter are:
(a) A/D converter and a
counter
(b) A/D converted and a
rectifier
(c) D/A converter and a
counter
(d) Ramp generator and
counter
(e) Comparator
(28) Which of the following
electrical equipment cannot convert ac into dc
(a) diode
(b) converter
(c) transformer
(d) mercury arc rectifier
(29) Voltage measurement are
often taken by using either a voltmeter or
(a) an ammeter
(b) an ohmmeter
(c) an oscillator
(d) a watt-meter
(30)The electric device
which blocks DC but allows AC is called:
(a) capacitance
(b) inductor
(c) an oscilloscope
(d) a watt-meter
(31 ) The range of an
ammeter can be extended by using a
(a) shunt in series
(b) shunt in parallel
(c) multiplier in series
(d) multiplier in parallel
(32)A device that changes
one form of energy to another is called
(a) rheostat
(b) oscillator
(c) transducer
(d) varicap
(33) Aquadag is used in CRO
to collect
(a) primary electron
(b) secondary electron
(c) both primary and
secondary
(d) none of above
(34) A vertical amplifier
for CRO can be designed for
(a) only a high gain
(b) only a broad bandwidth
(c) a constant gain time
bandwidth product
(d)all of the above
(35) One of the following is
active transducer
(a) Strain gauge
(b) Selsyn
(c) Photovoltic cell
(d) Photo emissive cell
(36) The dynamic characteristics
of capacitive transducer are similar to those of
(a) low pass filter
(b) high pass filter
(c) band pass filter
(d) band stop filter
(37) Thermocouples are
(a) passive transducers
(b) active transducers
(c) both active and passive
transducers
(d) output transducers
(38) The size of air cored
transducers as compare to iron core counter part are
(a) bigger
(b) smaller
(c) same
(39) From the point of view
of safety, the resistance of earthing electrode should be:
(a) low
(b) high
(c) medium
(d) the value of resistance
of electrode does not effect the safety
(40) In CRT the focusing
anode is located
(a) between pre accelerating
and accelerating anodes
(b) after accelerating
anodes
(c) before pre accelerating
anodes
(d) none of above
(41) Which transducer
converts heat energy into electrical energy
(a) I. V. D. T.
(b) thermocouple
(c) photoconductor
(d) none of the above
(42) Which of photoelectric
transducer is used for production of electric energy by converting
solar energy
(a) photo emission cell
(b) photo diode
(c) photo transistor
(d) both (b) and (c)
(43) Which of the following
instruments consumes maximum power during measurement?
(a) induction instruments
(b) hot wire instruments
(c) thermocouple instruments
(d) electrodynamometer
instruments
(44) Which of the following
meters has the best accurancy
(a) moving iron meter
(b) moving coil meter
(c) rectifier type meter
(d) thermocouple meter
(45) The function of the
safety resistor in ohm meter is to
(a) limit the current in the
coil
(b) increase the voltage
drop across the coil
(c) increase the current in
the coil
(d) protect the battery
(46) Which of the following
instruments is free from hysteresis and eddy current losses?
(a) M.l. instrument
(b) electrostatic instrument
(c) electrodynamometer type
instrument
(d)all of these
(47) The dielectric loss of
a capacitance can be measured by
(a) Wien bridge
(b) Owen bridge
(c) Schering bridge
(d) Maxwell bridge
(48) Reed frequency meter is
essentially a
(a) recording system
(b) deflection measuring system
(c) vibration measuring
system
(d) oscillatory measuring
system
(49) In measurements made
using a Q meter, high impedance elements should preferably be
connected in
(a) star
(b) delta
(c) series
(d) parallel
(50) A digital voltmeter
measures
(a) peak value
(b) peak-to-peak value
(c) rms value
(d) average value
BSNL TTA Question
Paper-Electrical Specialization 2007
1. In a D.C.
generator, if the brushes are given a small amount of forward shift, the effect
of
armature is
a. Totally demagnetizing
b. Totally magnetizing
c. Partly demagnetizing and partly cross magnetizing
d. Totally cross magnetizing
2. The air gap between
stator and armature of an electric motor is kept as small as possible
a. To get a stronger magnetic field
b. to improve the air circulation
c. To reach the higher speed of rotation
d. To make the rotation easier.
3. Two series motors
are coupled. One motor runs as generator and other as motor. The friction
losses of the two
machines will be equal when
a. Both operates at same voltage
b. Both have same back emf
c. Both have same speed
d. both have same excitation
4. Plugging of D.C.
motor is normally executed by
a. Reversing the field polarity
b. Reversing the armature polarity
c. Reversing both the armature and field polarity
d. Connecting a resistance across the armature.
5. Transformer oil
transformer provides
a. Insulation and cooling
b. B. Cooling and lubrication
c. Lubrication and insulation
d. Insulation, cooling and lubrication
6. Leakage fluxes of
transformer may be minimized by
a. Reducing the magnetizing current to the minimum
b. Reducing the reluctance of the iron core to the minimum
c. Reducing the number of primary and secondary turn to the
minimum
d. Sectionalizing and interleaving the primary and secondary
windings
7. Electric power is
transformed upon one coil to other coil in a transformer
a. Electrically
b. Electro Magnetically
c. Magnetically
d. Physically
8. The most suitable
and economical connection for small high voltage transformer isa.
Star- Delta connection
b. Delta- Delta connection
c. Delta- Star connection
d. Star- Star connection
9. An alternator is
said to be over excited when it is operating at
a. Unity power factor
b. Leading power factor
c. Lagging power factor
d. Either lagging or leading power factor
10. In an A.C.
machine, the armature winding is kept stationary while the field winding is
kept
rotating for the
following rason
a. Armature handles very large currents and high voltages
b. Armature friction involving deep slots to accommodate large
coils is easy if armature is kept
stationary
c. Ease of cooling the stator than rotor
d. None of the above.
11. In a synchronous
motor, the torque angle is the
a. Angle between the rotating stator flux and rotor poles
b. Angle between the magnetizing current and back emf
c. Angle between the supply voltage and back emf
d. None of the above
12. A 3-phase
synchronous motor is said to be "floating" when it operates
a. On no load and without loss
b. On constantly varying load
c. On pulsating load
d. On high load and variable supply voltage
13. Speed of
synchronous motor depends upon
a. Number of poles
b. Supply frequency
c. Both (a) and (b)
d. Neither (a) nor (b)
14. Imbalance in the
shaft of an induction motor occurs due to
a. Slip rings
b. Overheating of winding
c. Non uniform of air gap
d. Rigid consturcion
15. Squirrel cage
induction motor has
a. Zero starting torque
b. Very small starting torque
c. Medium starting torque
d. Very high starting torque
16. The principle of
operation of a 3-phase induction motor is similar to that of a
a. Synchronous motor
b. Repulsion - start induction motor
c. Transformer with a shorted secondary
d. Capacitor - start, induction - run motor
17. The speed/load
characteristics of a universal motor are similar to those
a. D.C. shunt motor
b. D.C. series motor
c. A.C. motor
d. None of the above
18. Single phase A.C.
motor generally used for vacuum cleaners is
a. Universal motor
b. Repulsion motor
c. Hysteresis motor
d. Reluctance motor
19. Buchholz relay is
used for the protection of
a. Switch yard
b. Transformers
c. Alternators
d. Transmission lines
20. The type of
braking used in traction system is
a. Mechanical braking
b. Electro - pneumatic braking
c. Vacuum braking system
d. All the above
21. The function of
processing zenger diode in a UJT circuit used for triggering of SCRs is to
a. Expedite the generation of triggering pulses
b. Delay the generation of triggering pulses
c. Provide a constant voltage to UJT to prevent erratic firing
d. Provide a variable voltage to UJT as the source voltage changes
22. The frequency of a
ripple in the output voltage of a 3 - phase semi converter depends upon
a. Firing angle and load resistance
b. Firing angle and supply frequency
c. Firing angle and load inductance
d. Only on load circuit parameters
23. The SCR is turned
off when the anode currents falls below
a. Forward current rating
b. Break - over voltage
c. Holding current
d. Latching
24. V4 characteristics
of emitter of a UJT is
a. Similar to CE with linear and saturation region
b. Similar to FET with a linear and pinch of region
c. Similar to tunnel diode in some respects
d. Linear between the peak point and valley point
25. A transformer
works on
a. DC
b. AC
c. AC & DC both
d. Neither AC not DC
26. Which of the
following device is used in transformer?
a. Tube light
b. Electric heater
c. Mobile phone
d. Rectifier module
27. Earth electrodes
can be in the form of
a. rods or piper
b. stripes
c. plates
d. any of above
28. Carbone or metal
brushes are used in
a. DC generators only
b. AC generators only
c. Both AC & DC generation
d. None of above
29. Energy is lost due
to Joule's heating effects in winding of transformer. This is called
a. Copper loss
b. Eddy current loss
c. Flux loss
d. None
30. In refrigeration
cycle heat is lost in
a. Cooling coil
b. Condenser
c. Compressor
d. Expansion valve
31. The power factor
of AC circuit is
a. R/X
b. R/Z
c. Z/R
d. Zero
32. Silicon controlled
output is good if ripple factor is
a. Switch
b. Transformer
c. Amplifier
d. None of above
33. The rectifier
output is good if ripple factor is\
a. More
b. Less
c. Constant
d. None of above
34. Protective relays
can monitor large AC current by means of
a. Current transformer
b. Potential transformer
c. Micro transformer
d. None of above
35. The combines AM of
two similar batteries connected in parallel is:
a. halved
b. doubled
c. remain constant
d. none of above
36. The current in
circuit having 5 V EMI source and 10 Ohm resistance is:
a. 2 Amp
b. 50 Amp
c. 5 Amp
d. ½ Amp
37. The chopper is a
device to change
a. Voltage
b. Current
c. Frequency
d. None of these
38. The power
consumption, in case of centrifugal loads (like pump, fan, blower etc) is
proportional to:
a. speed
b. square of speed
c. cube of speed
d. none of these
39. Which of these
need to be measured after rewinding the motor:
a. no load current
b. air gap
c. winding resistance
d. all of the above
40. Five percent
increase in supply frequency will change the synchronous speed of motor by:
a. -5%
b. +5%
c. -10%
d. +10%
41. Which of the following
is the best inverter?
a. square wave inverter
b. sine wave inverter
c. pure sine wave inverter
d. triangular wave inverter
42. For driving a
motor in a tape recorder or record player, the motor used is generally:
a. a synchronous motor
b. a hydraulic motor
c. an induction motor
d. a dc series motor
43. The DC motor
starter used with a constant speed shunt motor is:
a. 2 point starter
b. 3 point starter
c. 4 point starter
d. 5 point starter
44. A commutator in a
DC motor converts
a. AC to DC
b. DC to AC
c. Both AC to DC and DC to AC
d. None of these
45. Two transformers
running in parallel will share the load according to their:
a. leakage reactance
b. pu impedance
c. efficiency
d. rating
46. The size of the
Earth Wire is determined by:
a. the ampere capacity of the service wires
b. the atmospheric conditions
c. the voltage of service wires
d. none of these
47. The function of
lightning arrester is:
a. to limit the short circuit fault current
b. to provide path to high voltage surge to earth
c. to reduce arcing
d. none of these
48. Surge protector
provide:
a. high impedance to normal voltage
b. low impedance to surge
c. both (a) and (b)
d. none of these
49. Earthing is
necessary to give protection against
a. voltage fluctuation
b. overloading
c. danger of electric shock
d. high temperature of conductors
50. The primary
function of fuse is to
a. protect the appliance
b. open the circuit
c. prevent excessive current
d. protect the line
BSNL TTA Question
Paper Control Systems Specialization 2007
1. An open loop
control system has its
(a) control action independent of the output or desired quantity
(b) controlling action, depending upon human judgment
(c) internal system changes automatically taken care of
(d) both (a) and (b)
(e) all (a),(b) and (c)
2. A servo system must
have
(a) feedback system
(b) power amplifier to amplify error
(c) capacity to control position or its derivative
(d) all of these
(e) none of these
3. The major
disadvantage of a feedback system may be
(a) Inaccuracy
(b) inefficiency
(c) Unreliability
(d) instability
(e) Insensitivity
4. Properties of a
transfer function
(a) It is ratio of two polynomials is S and assumes zero initial
conditions
(b) It depends on system elements and not input and output of the
system
(c) Coefficients of the powers of S in denominator and numerator
are all real constant. The order of
denominator is usually greater than or equal to the order of
numerator
(d) All of these
(e) It is a function which transfer one physical system into
another physical system.
5. The classical
analogous of a simple lever is
(a) Capacitor bridge
(b) transformer
(c) mutual inductor
(d) either of these
6. Two blocks G1(s)
and G2(s) can be cascaded to get resultant transfer function as
(a) G1(s) + G2(s)
(b) G1(s) / G2(s)
(c) G1(s) G2(s)
(d) 1+G1(s) G2(s)
(e) 1-G1(s)G2(s)
(f) two blocks cannot be cascaded
7. The principles of
homogeneity and super position can be applied to
(a) linear time invariant system
(b) non-linear time invariant system
(c) digital control system
(d) both (a) and (b)
8. Pick up the
nonlinear system
(a) automatic voltage regulator
(b) d.c. servomotor with high field excitation
(c) temperature control of a furnaces using thermistor
(d) speed control using SCR
(e) all of these
9. Signal flow graph
(SFG) is a
(a) polar graph
(b) semi log graph
(c) log log graph
(d) a special type of graph for analyzing modem control system
(e) a topological representation of a set of differential
equations
10. Disadvantages of
magnetic amplifier
(a) time lag, less flexible, non-sinusoidal waveform
(b) low power consumption and isolation of the active circuit
(c) saturation of the core
(d) all of these
11. Pick up false
statement regarding magnetic amplifiers
(a) The gate coil of an ideal magnetic amplifier has either zero
or infinite inductance
(b) Resistance of control and gate winding is very small
(c) Magnetic amplifier gas dropping load characteristics
(d) Magnetic amplifiers are not used to control the speed of d.c.
shunt motor
(e) Magnetic amplifiers can be used in automatic control of
electric drivers of higher rating.
12. High power
amplification is achieved by using
(a) push pull amplifier
(b) amplidyne
(c) magnetic amplifier
(d) DC amplifier
(e) D.C. generator
13. Pick up false
statement regarding servomotors
(a) The d.c. servomotors are lighter than equivalent a.c.
servomotors
(b) The d.c. servomotors develops higher starting and reversing
torque than equivalent a.c. servomotor.
(c) A drag cup a.c. servomotor has one windings on stator and
other on rotor
(d) Output power of servomotors varies from 1/20 W to 100 W
14. To reduce steady
state error
(a) decrease natural frequency
(b) decrease damping
(c) increase damped frequency
(d) increase time constant
(f) increase gain constant of the system
15. A good factor for
Mp should be
(a) less than 1
(b) lying between 1.1 and 1.5
(c) more than 2.2
(d) zero
(e) infinity
16. Pick up false
statement. Routh-Hurwitz criterion
(a) is used for determining stability of a system
(b) is an algebraic procedure
(c) gives the exact location of roots of the characteristic
equation
(d) does not indicate relative degree of stability or instability
17. Which of the
following is the time domain method of determining stability of a control
system
(a) Bode plot
(b) Nyquist plot
(c) Nicholos chart
(d) Routh-Hurwitz array
(e) Constant M and (fy) locus
(f) Root locus technique
18. The technique
which gives transient response quickly as well as stability information is
(a) Nyquist plot
(b) Routh-Hurwitz criteria
(c) Bode plot
(d) Root locus plot
(e) Nichols plot
19. The bandwidth can
be increased by use of
(a) phase lag network
(b) phase lead network
(c) both (a) and (b) in cascade
(d) both (a) and (b) in parallel
(e) none of these
20. Nyquist plot is
drawn on
(a) semi log graph paper
(b) log log graph paper
(c) polar graph paper
(d) centimeter graph paper
21. If the gain margin
is positive and the phase margin is negative the system is
(a) stable
(b) unstable
(c) indeterminist
22. The Bode plot is
applicable to
(a) all phase network
(b) minimum phase network
(c) maximum phase network
(d) lag lead network
(e) none of these
23. The valid relation
between setting time ts and rise time tr is
(a) tr>ts
(b) ts>tr
(c) ts=tr
(d) none of these
24. As a root moves
further away from imaginary axis the stability
(a) increases
(b) decreases
(c) not affected
(d) none of these
25. Flat frequency
response means that the magnitude ratio of output to input over the
bandwidth is
(a) variable
(b) zero
(c) constant
(d) none of above
26. How many octaves
are between 200 Hz and 800 Hz
(a) Two octave
(b) One octave
(c) Four octave
(d) None of above
27. Human system can
be considered as
(a) open loop system
(b) close loop system with single feedback
(c) close loop system with multivariable feedback
(d) none of these
28. In a feedback
system the transient response
(a) Decays at constant rate
(b) gets magnified
(c) decays slowly
(d) decays more quickly
29. Transfer function
of a system is used to calculate
(a) the steady state gain
(b) the main constant
(c) the order of system
(d) the output for any given input
(e) all of the above
30. Transfer function
of a system is defined as the ratio of output to input in
(a) Laplace transform
(b) Z-transform
(c) Fourier transform
(d) Simple algebraic form
31. Introduction of
feedback decreases the effect of
(a) disturbances
(b) noise signals
(c) error signals
(d) all the above
32. The system
response of a system can be best tested with
(a) unit impulse input signal
(b) ramp input signal
(c) sinusoidal input signal
(d) exponentially decaying input signal
33. Which of the
following is a closed loop system
(a) electric switch
(b) car starter
(c) de generator
(d) auto-pilot for an aircraft
34. Which of the
following is used as an error detector
(a) potentiometer
(b) field controlled ac motor
(c) amplidyne
(d) armature controlled ac motor
35. The break away
point of root loci are
(a) open loop poles
(b) closed loop poles
(c) open loop zeros
(d) closed loop zeros
36. Noise in a control
system can be kept low by
(a) reducing the bandwidth
(b) attenuating such frequencies at which external signals get
coupled into the system
(c) both (a) and (b)
(d) none of these
37. Main cause of
absolute instability in the control system is
(a) parameters of controlling system
(b) parameters of controlled system
(c) parameters of feedback system
(d) error detector where the two signals are compared
38. Basically a
controller is
(a) a amplifier
(b) a clipper
(c) a comparator
(d) a summer
39. A system with gain
margin close to unity or a phase margin close to zero is
(a) highly stable
(b) highly oscillatory
(c) relatively stable
(d) none of these
40. Which of following
elements is not used in an automatic control system
(a) sensor
(b) error detector
(c) oscillator
(d) final control element
41. AC systems are usually
preferred to the DC systems in control applications because
(a) AC systems are cheaper
(b) AC systems are more stable
(c) AC systems have better performance characteristics and smaller
in size
(d) all of these
42. A system has the
transfer function (1-s)/(1+s); It is known as
(a) low pass system
(b) high pass system
(c) all pass system
(d) none of the above
43. In control
systems, excessive bandwidth should be avoided because
(a) noise is proportional to bandwidth
(b) it leads to low relative stability
(c) it leads to slow speed of response
(d) none of these
44. In most systems,
an increase in gain leads to
(a) larger damping ratio
(b) smaller damping ratio
(c) constant damping ratio
(d) none of these
45. A step function is
applied to the input of a system and output is of the form y = t, the system is
(a) stable
(b) unstable
(c) not necessarily stable
(d) conditionally stable
46. Which of the
following can be magnified by magnetic amplifier
(a) voltage
(b) current
(c) power
(d) none of above
47. The inductance is
not used in lag network because of
(a) big size
(b) time delay and hysteresis losses
(c) high reactance
(d) none of these
48. Saturation in a
stable control system can cause
(a) conditional stability
(b) over damping
(c) low level oscillations
(d) high level oscillations
49. Excessive noise in
control systems can cause
(a) reduction in bandwidth
(b) reduction in gain
(c) saturation in amplifying stages
(d) oscillations
50. The type-0 system
has
(a) net pole at the origin
(b) no pole at the origin
(c) simple at one origin
(d) two poles at the origin
BSNL TTA Question
Paper-Computers Specialization 2007
1. What is the name of
the software that allows us to browse through web pages?
(a) Browser
(b) Mail Client
(c) FTP Client
(d) Messenger
2. What is the address
given to a network called?
(a) System Address
(b) SYSID
(c) Process ID
(d) IP Address
3. Which one of the
following is a valid DOS command?
(a) LIST *.*
(b) LIST???.???
(c) RECOVER A:
(d) RENAME A:SAMPLE.TXT C:TEST.DOC
4. All system settings
in WINDOWS are stored in:
(a) CONTROL.INI
(b) MAIN.INI
(c) SYSTEM.INI
(d) SETTING.INI
5. Which number system
is usually followed in a typical 32-bit computer?
(a) 2
(b) 10
(c) 16
(d) 32
6. Which of the
following is not an output device:
(a) Printer
(b) Scanner
(c) Flat Screen
(d) Touch Screen
7. A microprocessor is
a processor with reduced
(a) instruction set
(b) power requirement
(c) MIPS performance
(d) none of the above
8. Which of the
following is not an output of an assembler?
(a) executable program
(b) source listing with line numbers and errors
(c) a symbol table
(d) object program
9. Which layer of OSI
model is responsible for routing and flow control:
(a) Presentation
(b) Transport
(c) Network
(d) Data Link
10. Arrays are passed
as arguments to a function by
(a) value
(b) reference
(c) both a and b
(d) none of the above
11. Array is:
(a) linear data structure
(b) non-linear structure
(c) none of the above
12. A data structure
in which elements are added and removed from only one end, is known as:
(a) Array
(b) Stack
(c) Queue
(d) None of the above
13. A diamond-shaped
box in an Entity-Relationship diagram refers to:
(a) Entity
(b) Relationship
(c) Attribute
14. The principle
means of identifying entities within an entity set is:
(a) Primary Key
(b) Record
(c) Attribute
(d) Tuple
15. Modem refers to:
(a) Modulator
(b) Modulation
(c) Demodulator
(d) Modulator and Demodulator
16. C language is
available for which of the following Operating Systems?
(a) DOS
(b) Windows
(c) Unix
(d) All of the above
17. Which of the
following have the fastest access time?
(a) Magnetic Tapes
(b) Magnetic Disks
(c) Semiconductor Memories
(d) Compact Disks
18. DMA stands for:
(a) Direct Memory Allocation
(b) Distinct Memory Allocation
(c) Direct Memory Access
(d) Distinct Memory Access
19. Array subscripts
in C always start at:
(a):1
(b) 0
(c) 1
(d) Value provided by user
20. Which type of
commands in DOS needs additional files for their execution?
(a) Batch Commands
(b) Internal Commands
(c) External Commands
21. Which of the
following statements in regard to Directories is false?
(a) Directories can exist inside directories
(b) The root directory is always at the highest level
(c) Directories with files can be deleted
(d) Directories cannot be renamed
22. It is better to
buffer a table when
(a) When a table is read infrequently
(b) When a table is linked to check tables
(c) When a table is read frequently and the data seldom changes
(d) When a single record is to be picked up
23. The Operating
System is responsible for:
(a) Controlling peripheral devices such as monitor, printers, disk
drives
(b) Provide an interface that allows users to choose programs to
run and to manipulate files
(c) Manage users' files on disk
(d) All of the above
24. A company whishes
to connect two sites in different parts of the country together. It is decided
to use the telephone
system. What device should be connected to the fileservers on each site?
(a) Router
(b) Modem
(c) Switch
(d) Hub
25. What is a file
server?
(a) A computer that performs a service for other computers
(b) A computer that controls the printers on the network
(c) A computer that stores files that are created by network users
26. What is the
Protocol used for the Internet?
(a) IPX/SPX
(b) NetBIOS/NetBEUI
(c) CDMA/CA
(d) TCP/IP
27. Which one of the
following is not a Normal Forms (Normalization) rule with regards to the
Relational Model?
(a) All fields within a table must relate to or directly describe
the Primary Key.
(b) Repeating Groups must be eliminated from tables.
(c) Fields that can contain non-numeric data are to be removed and
placed within their own tables with
an associated Primary Key.
(d) Redundant data is to be eliminated by placing the offending
fields in another table.
28. Choose the answer
which best describes the term Primary Key:
(a) The Primary Key is a field that contains data that can be
duplicated.
(b) The Primary Key is a field that contains data that is unique.
(c) The Primary Key is a field that is never associated with any
field in other tables.
(d) The Primary Key field is a concept used only in Microsoft
Access.
29. Which technique is
used to reduce the size of a file:
(a) Compression
(b) Decompression
(c) Encryption
(d) Decryption
30. BIOS stands for
(a) Binary Input Output Set
(b) Binary Input Output System
(c) Basic Input Output Set
(d) Basic Input Output System
31. A floppy disk is
consisting of 40 tracks, each track contains 100 sectors, and the capacity of a
sector is 512 bytes,
what is the approx. size of that disk?
(a) 1 MB
(b) 2 MB
(c) 4 MB
(d) 8 MB
32. What is the binary
equivalent of a decimal number 68:
(a) 1000100
(b) 1100100
(c) 1000010
(d) 1000001
33. Assembly language
to machine language translation is:
(a) One-to-One
(b) One-to-Many
(c) Many-to-One
(d) Many-to-Many
34. Maximum size of IP
address is:
(a) 12 bits
(b) 24 bits
(c) 32 bits
(d) 48 bits
35. RAM stands for
(a) Read Access Memory
(b) Read After Memory
(c) Random Access Memory
(d) Random After Memory
36. What is the final
value of sum?
main ()
{
int sum=1;
for(;sum<=9;)
printf(%d\n, ++sum);
}
(a) 9
(b) 10
(c) 11
(d) none of the above
37. If c is a variable
initialized to 1, how many times the following loop be executed:
while(c>0 && c<60)
{
c++;
}
(a) 59
(b) 60
(c) 61
(d) none of the above
38. The declaration
void fun(int) indicates the fun is a function which:
(a) has no arguments
(b) returns nothing
(c) both a and b
(d) none of the above
39. Out of the
following which is not valid network topology:
(a) Bus
(b) Star
(c) Circle
(d) Tree
40. The overall
logical structure of a database can be expressed graphically by:
(a) Data Flow Diagram
(b) Flow Chart
(c) Directed Graph
(d) Entity-Relationship Diagram
41. CARRY, in a
half-adder, can be obtained using:
(a) OR gate
(b) AND gate
(c) EX-OR gate
(d) EX-AND gate
42. The memory that
requires refreshing of data is:
(a) SROM
(b) DROM
(c) SRAM
(d) DRAM
43. The minimum number
of bits required to represent numbers in the range:28 to +31 is-
(a) 5
(b) 6
(c) 7
(d) 8
44. Which bus carries
information between processors and peripherals?
(a) Data bus
(b) Control bus
(c) Address bus
(d) Information bus
45. Which part of the
computer perform arithmetic calculations?
(a) Control unit
(b) Registers
(c) ALU
(d) CPU
46. A gigabyte
represents:
(a) 1 billion bytes
(b) 1000 kilobytes
(c) 230 bytes
(d) 10 megabytes
47. The minimum number
of bits required to store the hexadecimal number FF is:
(a) 2
(b) 4
(c) 8
(d) 16
48. Cache memory
enhances:
(a) memory capacity
(b) memory access time
(c) secondary storage capacity
(d) secondary storage access time
49. A UPS:
(a) increases the storage capacity of a computer system
(b) increases the processor speed
(c) provides backup power in the event of a power cut\
(d) none of the above
50. An RDBMS is a:
(a) Remote DBMS
(b) Relative DBMS
(c) Reliable DBMS
(d) Relational DBMS
BSNL TTA Question
Paper-Communication Specialization 2007
(1) The most common
modulation system used for telegraphy is
(a) FSK
(b) PSK.
(c) PCM
(d) single tone modulation
(e) Two tone modulation
(2)VSB is an
abbreviation of vestigal sideband, is derived by filtering
(a) DSB
(b) AM
(c) either (a) or (b)
(d) PM
(3) The Hartely law
states that
(a) The maximum rate of information transmission depends on the
depth of modulation
(b) The maximum rate of information depends on the channel
bandwidth.
(c) Only binary codes may be used
(d) Redundancy is essential
(4) The FM signal
with, a modulation index mf is passed through a frequency tripler. The wave in
the output of the
tripler will have a modulation index of
(a) mf/9
(b) mf/3
(c) mf
(d) 3 mf
(e) 9mf
(5) In high power AM
transmission, modulation is done at
(a) Buffer stage
(b) Oscillator stage
(c) RF power stage
(d) If stage
(6) Companding is used
(a) In delta modulator to combat noise
(b) To limit amplitude in PCM transmitters.
(c) In PWM for working it with TDM
(d) To protect small signals in PCM from quantizing distortion
(e) In PCM to reduce the SNR
(7) In PCM system the
SNR of the output signal increases
(a) Inversely with bandwidth
(b) Exponential with bandwidth
(c) With rate of sampling
(d) At low frequencies only
(8) Armstrong
modulator generates
(a) Phase modulated signal
(b) Frequency modulated signal
(c) Both of these
(d) Pulse code modulated signal
(e) AM and PCM signals
(9) A Klystron is a
cavity acting as buncher and catcher is used as microwave tube for
(a) Guiding waves
(b) Velocity modulation
(c) frequency modulation
(d) impedance matching
(e) All of these
(10) Easily adjustable
tuning component in a waveguide is
(a) plunger
(b) plunger and stub
(c) screw
(d) both (a) and (c)
(e) both (b) and (c)
(11) A ferrite is
(a) A non-conductor with magnetic properties
(b) A conductor with magnetic properties
(c) A semiconductors
(d) An insulator which attenuates magnetic fields
(e) A compound with good conductivity.
(12) Vacuum tubes
eventually fail at microwave frequencies because of their
(a) Inter electrode capacitance
(b) Small series inductance
(c) Large shunt capacitance
(d) Short transit time
(e) Increased noise figure
(13) The biggest
disadvantage the IMP ATT diode has is its
(a) Low Efficiency
(b) high noise
(c) Low BW
(d) inability to provide pulse operation
(e) low power handling ability
(14) In AM
transmission the frequency, which is not transmitted is
(a) carrier frequency
(b) audio frequency
(c) upper side frequency
(d) lower side frequency
(15) FM broadcast band
lies in
(a) VHF
(b) UHF
(c) SHF
(d) HF
(16) Automatic gain
control is used
(a) to maintain the tuning correct
(b) to reduce the voltage of loud passage of music
(c) to maintain the same amount of output, when stations of
different strength are received
(d) to increase the amplification at high frequencies
(17) The modulation
system inherently is most noise resistant in
(a) SSB suppressed carrier
(b) FM
(c) PPM
(d) PCM
(18) In practical
waveguide act as
(a) low pass filter
(b) high pass filter
(c)band pass filter
(d)band stop filter
(19) The antenna
efficiencies achieved in practice depend upon
(a) wave length
(b) impedance
(c) frequency
(d) none of above
(20) The process of
compressing the digital codes at the transmitter and then expanding them
back to their original
form at receiver is known as
(a) Quantizing
(b) companding
(c) step sizing
(d) modulation
(21) Digital
transmission efficiency is given by
(a) information bits/total bits
(b) total bits/information bits
(c) redundant bits/information bits
(d) none of the above
(22) The speed of BRI
ISDN interface is
(a) 2B + D
(b) 2D + B
(c) 30B + D
(d) 30D + B
(23) Which of the
following is not a microwave generation source?
(a) Klystron
(b) Magnetron
(c) TWT
(d) Diode
(24) A signal of
maximum frequency of 1 KHz is sampled at Nyquist Rate. The interval between
two successive samples
is:
(a) 50 micro seconds
(b) 100 micro seconds
(c) 500 micro seconds
(d) 1000 micro seconds
(25) In order to get
back the original signal, it is necessary to use:
(a) low pass filter
(b) high pass filter
(c) band pass filter
(d) band reject filter
(26) Man made noise id
caused by:
(a) Solar eruptions
(b) Distant Stars
(c) Lightning Discharges
(d) Arc discharge in electric machines
(27) At microwave
frequencies, the size of antenna becomes
(a) very large
(b) large
(c) small
(d) very small
(28) Due to curvature
of earth, microwave repeaters are placed at distance of about
(a) l0 Km
(b) 50 Km
(c) 200 Km
(d) 500 Km
(29) For handling
large microwave power, the best medium is
(a) coaxial line
(b) rectangular waveguide
(c) stripline
(d) circular wave guide
(30) An attenuator is
used with TWT to
(a) prevent oscillations
(b) increase gain
(c) prevent saturation
(d) help bunching
(3l) TWT is basically
(a) an oscillator
(b) tuned amplifier
(c) wideband amplifier
(d) an audio amplifier
(32) The negative
resistance in Gunn diode is due to
(a) electron transfer to a less mobile energy level
(b) high reverse bias
(c) electron domain formation at the junction
(d) tunneling across the junction
(33) Which of the
following sinusoidal oscillator is preferred for microwave frequencies?
(a) resonant circuit oscillator
(b) RC phase shift oscillators
(c) negative resistance oscillators
(d) all of the above
(34) When
electromagnetic waves are propagated in a waveguide
(a) they travel along the walls of the waveguide
(b) they travel through the dielectric without touching the walls
(c) they are reflected from the walls but do not travel along the
walls
(d) none of above
(35) Wave guides are
generally made of
(a) Cast iron or steel
(b) White metal or gun metal
(c) bronze or aluminium
(d) plastic or bakelite
(36) The cut off
frequency of a wave guide means
(a) lower frequencies will not be propagated
(b) it determines the dimensions of the wave guide
(c) frequency at which zero transmission takes place
(d) None of above
(37) In case of
matched load
(a) Transmission is zero
(b) reflection is zero
(c) reflection is unity
(d) transmission is equivalent to reflection
(38) In an AM wave
with 100% modulation, the carrier is suppressed. The percentage of power
saving will be
(a) 100%
(b) 50%
(c) 25%
(d) 66.7%
(39) The function of
AM detector circuit is
(a) to rectify the input signal
(b) to discard the carrier
(c) to provide the audio signal
(d) All of the above
(40) In FM, the noise
can be further decreased by
(a) decreasing deviation
(b) increasuig deviation
(c) keeping deviation constant
(d) none of these
(41) In PPM, message
resides in
(a) Pulses
(b) time location of pulse edges
(c) none of these
(42) Which of the
following pulse systems is preferred for communication in presence of noise?
(a) PAM
(b) PDM
(c) PPM
(d) none of above
(43) Which of the
following pulse systems requires higher bandwidth
(a) PAM
(b)PDM
(c)PPM
(d)none of these
(44) The audio
frequency range lies between
(a) 20 to 20,000 Hz
(b) 20 to 20,000 KHz
(c) 400 to 8,000Hz
(d) 500 to 5,000 Hz
(45) Maximum
undistorted power output of a transmitter is obtained when its modulation is:
(a) more than 100%
(b) 100%
(c) less than 100%
(d) 50%
(46) The AGC voltage
in a radio receiver is proportional to
(a) the amount of modulation
(b) the amplitude of audio signal
(c) the amplitude of IF carrier
(d) none of these
(47) An FM transmitter
has maximum frequency deviation of 75 KHz and reproduces audio
signal up to 15 KHz.
Minimum channel width required, in KHz is
(a) 180
(b) 120
(c) 90
(d) 60
(48) With 100%
modulation, ratio of side band power to total power transmitted in an amplitude
modulated wave is
(a) 2/3
(b) l/3
(c) l/2
(d) l/4
(49) To increase the Q
factor of an induction, it wound with
(a) thicker wire
(b) thinner wire
(c) longer wire
(d) wire with heavy insulation
(50) Power factor of a
purely resistive circuit is:
(a) zero
(b) one
(c) 0.5
(d) infinity
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