BEL Previous year Placement Technical Papers
1. The gray code equivalent of binary 1100 is
a. 1011 b. 1101 c. 1010 d. 1100
2. A Multiplexer has
a. Multiple inputs and single output
b. Single input and Multiple outputs
c. Multiple inputs and Multiple outputs
d. Multiple inputs for Storage of Data
3. A binary half adder
a. Adds two binary digits and produces their sum and carry
b. Adds half the sum to the carry
c. Adds two binary digits and carry from previous addition
d. Adds two binary digits at half the speed
4. An index register in a computer is for
a. Arithmetic and logic functions
b. Storage of results
c. Modifying the address
d. Counting the no of programmes
5. An example of volatile memory is
a. RAM b. ROM c. EPROM d. Magnetic tape
6. Barrier voltage in a P-N junction is caused by
a. Thermally generated electrons and holes
b. Diffusion of majority carriers across the junction
c. Migration of minority carriers across the junction
d. Flow of drift current
7. The temperature coefficient of an intrinsic semiconductor is
a. Positive b. Negative c. Zero d. Like metals
8. A silicon transistor has a leakage current 1cbo = 1 ma. If the temp. rises by 50o C the leakage current will be
a. 30 ma b. 32ma c. 50ma d. no change
9. The noise figure of an ideal amplifier in decibel is
a. 0.5 b. 0 c. 1 d. 10
10. The rise time of an amplifier is 200 nsec. Its bandwidth is
a. 70MHz b. 140MHz c. 100MHz d. 1.75Mhz
11. MOSFET operates in
a. Depletion mode only
b. Enhancement mode only
c. Depletion and enhancement mode
d. None of these of the above
12. A device which behaves like SCRs is
a. UJT b. Triac c. MOSFET d. SRD
13. A plate modulated class C RF amplifier produces 100 KW of radiated power at 100 % modulation. The modulating audio amplifier supplies approximately
a. 25KW b. 33KW c. 50KW d. 66KW
14. A 100 MHz FM carrier, modulated by a 5 KHz sine wave deviates by 50 KHz
If the frequency of the modulating sine wave is doubled, the deviation will
a. Double b. Half c. Quadruple d. Have no change
15. Noise generated by a resistor is dependent on
a. Its Value
b. Its temperature
c. Both value and temp
d. None of these
16. A 32 channel 8 bit PCM system samples at 8 KHz rate. The overall bit rate in kilobits per second will be
a. 2048 b. 2000 c. 1920 d. 64
17. Stub matching eliminates standing wave on
a. Load side of the stub
b. Source side of the stub
c. Both sides
d. On the stub
18. A half wave folded dipole has a radiation resistance of
a. 72 W b.50W c. 144W d. 288W
19. Top loading is used in antennas for
a. Decrease in impedance
b. Increase in bandwidth
c. Increase in effective height
d. Decease the height
20. The term critical frequency in Ionospheric propagation is
a. Lowest frequency reflected by Ionosphere
b. Highest frequency reflected by the Ionosphere at vertical incidence
c. Lowest frequency reflected by the Ionosphere at vertical incidence
d. Lowest communication frequency possible
21. The cathode ray oscilloscope can be used to measure
a. Frequency b. Time interval c. Voltage d. All the above
22. A wein bridge is used for measurement of
a. Resistance b. Capacitance c. Inductance d. Audio frequency
23. The frame rate per second used in India TV is
a. 60 b. 50 c. 25 d. 30
24. VHF signals are propagated
a. Via the ionosphere
b. Along the ground
c. Through the troposphere
d. By reflection in ionosphere
25. The impedance of a 3 element yagi antenna is around
a. 75W b. 300W c. 50W d. 100W
26. A PIN diode is microwave
a. Oscillator b. Mixer c. Detector d. Switch
27. A transmission line of VSWR 2 has a reflection coefficient
a. 0.25 b. 0.5 c. 75 d. 0
28. Microwave repeaters are typically
a. 25 b. 50 c. 75 d. 100 Kms apart
29. To overcome fading in a ship-to-ship communication system we can efficiently use
a. Broadband Antenna
b. Directional Antenna
c. Space Diversity
d. Frequency Diversity
30. Frequency in the UHF range is propagate by waves of
a. Ground b. sky c. Space d. Surface
31. A duplexer is used to
a. Receive two signals in one antenna
b. Prevent interference between two antenna
c. Mix two signals to the same antenna
d. Allow one antenna for both transmission and reception
32. Strapping is used in a magnetron to
a. Prevent mode jumping
b. Reduce frequency drift
c. Ensure proper bunching
d. Dissipate heat
33. A rectangular waveguide behaves like a filter of
a. Band pass b. High pass c. Low pass d. Band stop
34. The signal propagation time in milliseconds for a geosynchronous satellite is
a. 540 b. 270 c. 135 d. 100
35. The silicon solar cell is a
a. Photo conductive
b. Photo emissive
c. Photo voltaic
d. Photo resistive
36. For the national TV and ratio network, INSAT-IB uses
a. 400MHz b. 2.5GHz c. 2.5 and 5GHz d. 4 and 6 GHz
37. A typical fibre-optic detector is
a. Step recovery diode
b. Light emitting diode
c. Avalanche photo diode
d. Field effect transistor
38. A modem is a device used for
a. Digitizing voice data
b. Transmission of data on lines
c. Modulating and demodulating signals sent on a line
d. Suppressing noise interference
39. The most effective anti-jamming technique is
a. Frequency hopping
b. Spread Spectrum
c. Frequency synthesis
d. Burst transmission
40. Mono-mode is a term used in
a. Fibre-optics
b. Radar
c. Satellite communication
d. Magnetics
41. Monopulse technique is used in
a. Radar
b. Radio relay
c. Data communication
d. Fibre-optics
42. HDLC is a term for
a. Data communication protocol
b. Synchronizing pulses
c. Gain control in receivers
d. Error checking
43. A gateway
a. Is a place where radars are connected
b. Permits dissimilar networks to communicate
c. Bifurcates the RF path of a transmitter
d. Is a feeder cable
44. Ethernet is a name of
a. Medium of computer communication
b. Network for computer communication
c. Procedures for computer communication network
d. Software for computer communication
45. If several stations in a network want to use a single channel without interfering with one another, the technique used is called
a. Carrier sense
b. Phantom-freeze
c. Packet switching
d. Multiplexing
46. In a monolithic IC, resistors are formed from
a. Ceramic materials
b. Copper
c. P-type semiconductor
d. Aluminium deposition
47. ICs made by sputtering of materials on a ceramic substrate are called
a. Monolithic b. Hybrid c. Thick film d. Thin film
48. Two coils (inductors) connected in series have a combined inductance of 15mH. When terminals of one of the coils are reversed and connected to the other, the combined inductance is measured to be 9mH. What is the value of mutual inductance
a. 1.5mH b.3mH c.6mH d.12mH
49. If a parallel LC circuit is excited at frequency less than its resonant frequency, the nature of its effective impedance is
a. Resistive b. Inductive c. Capacitive d. None of these of these
50. The wave length of 1 Giga hertz frequency signal is
a. 10cm b. 30cm c. 3cm d. 1cm
51. Which of the following microwave tubes can be considered as broad band devices
a. Magnetrons
b. Klystrons
c. Reflex klystrons
d. Traveling wave tubes[TWT]
1. The gray code equivalent of binary 1100 is
a. 1011 b. 1101 c. 1010 d. 1100
2. A Multiplexer has
a. Multiple inputs and single output
b. Single input and Multiple outputs
c. Multiple inputs and Multiple outputs
d. Multiple inputs for Storage of Data
3. A binary half adder
a. Adds two binary digits and produces their sum and carry
b. Adds half the sum to the carry
c. Adds two binary digits and carry from previous addition
d. Adds two binary digits at half the speed
4. An index register in a computer is for
a. Arithmetic and logic functions
b. Storage of results
c. Modifying the address
d. Counting the no of programmes
5. An example of volatile memory is
a. RAM b. ROM c. EPROM d. Magnetic tape
6. Barrier voltage in a P-N junction is caused by
a. Thermally generated electrons and holes
b. Diffusion of majority carriers across the junction
c. Migration of minority carriers across the junction
d. Flow of drift current
7. The temperature coefficient of an intrinsic semiconductor is
a. Positive b. Negative c. Zero d. Like metals
8. A silicon transistor has a leakage current 1cbo = 1 ma. If the temp. rises by 50o C the leakage current will be
a. 30 ma b. 32ma c. 50ma d. no change
9. The noise figure of an ideal amplifier in decibel is
a. 0.5 b. 0 c. 1 d. 10
10. The rise time of an amplifier is 200 nsec. Its bandwidth is
a. 70MHz b. 140MHz c. 100MHz d. 1.75Mhz
11. MOSFET operates in
a. Depletion mode only
b. Enhancement mode only
c. Depletion and enhancement mode
d. None of these of the above
12. A device which behaves like SCRs is
a. UJT b. Triac c. MOSFET d. SRD
13. A plate modulated class C RF amplifier produces 100 KW of radiated power at 100 % modulation. The modulating audio amplifier supplies approximately
a. 25KW b. 33KW c. 50KW d. 66KW
14. A 100 MHz FM carrier, modulated by a 5 KHz sine wave deviates by 50 KHz
If the frequency of the modulating sine wave is doubled, the deviation will
a. Double b. Half c. Quadruple d. Have no change
15. Noise generated by a resistor is dependent on
a. Its Value
b. Its temperature
c. Both value and temp
d. None of these
16. A 32 channel 8 bit PCM system samples at 8 KHz rate. The overall bit rate in kilobits per second will be
a. 2048 b. 2000 c. 1920 d. 64
17. Stub matching eliminates standing wave on
a. Load side of the stub
b. Source side of the stub
c. Both sides
d. On the stub
18. A half wave folded dipole has a radiation resistance of
a. 72 W b.50W c. 144W d. 288W
19. Top loading is used in antennas for
a. Decrease in impedance
b. Increase in bandwidth
c. Increase in effective height
d. Decease the height
20. The term critical frequency in Ionospheric propagation is
a. Lowest frequency reflected by Ionosphere
b. Highest frequency reflected by the Ionosphere at vertical incidence
c. Lowest frequency reflected by the Ionosphere at vertical incidence
d. Lowest communication frequency possible
21. The cathode ray oscilloscope can be used to measure
a. Frequency b. Time interval c. Voltage d. All the above
22. A wein bridge is used for measurement of
a. Resistance b. Capacitance c. Inductance d. Audio frequency
23. The frame rate per second used in India TV is
a. 60 b. 50 c. 25 d. 30
24. VHF signals are propagated
a. Via the ionosphere
b. Along the ground
c. Through the troposphere
d. By reflection in ionosphere
25. The impedance of a 3 element yagi antenna is around
a. 75W b. 300W c. 50W d. 100W
26. A PIN diode is microwave
a. Oscillator b. Mixer c. Detector d. Switch
27. A transmission line of VSWR 2 has a reflection coefficient
a. 0.25 b. 0.5 c. 75 d. 0
28. Microwave repeaters are typically
a. 25 b. 50 c. 75 d. 100 Kms apart
29. To overcome fading in a ship-to-ship communication system we can efficiently use
a. Broadband Antenna
b. Directional Antenna
c. Space Diversity
d. Frequency Diversity
30. Frequency in the UHF range is propagate by waves of
a. Ground b. sky c. Space d. Surface
31. A duplexer is used to
a. Receive two signals in one antenna
b. Prevent interference between two antenna
c. Mix two signals to the same antenna
d. Allow one antenna for both transmission and reception
32. Strapping is used in a magnetron to
a. Prevent mode jumping
b. Reduce frequency drift
c. Ensure proper bunching
d. Dissipate heat
33. A rectangular waveguide behaves like a filter of
a. Band pass b. High pass c. Low pass d. Band stop
34. The signal propagation time in milliseconds for a geosynchronous satellite is
a. 540 b. 270 c. 135 d. 100
35. The silicon solar cell is a
a. Photo conductive
b. Photo emissive
c. Photo voltaic
d. Photo resistive
36. For the national TV and ratio network, INSAT-IB uses
a. 400MHz b. 2.5GHz c. 2.5 and 5GHz d. 4 and 6 GHz
37. A typical fibre-optic detector is
a. Step recovery diode
b. Light emitting diode
c. Avalanche photo diode
d. Field effect transistor
38. A modem is a device used for
a. Digitizing voice data
b. Transmission of data on lines
c. Modulating and demodulating signals sent on a line
d. Suppressing noise interference
39. The most effective anti-jamming technique is
a. Frequency hopping
b. Spread Spectrum
c. Frequency synthesis
d. Burst transmission
40. Mono-mode is a term used in
a. Fibre-optics
b. Radar
c. Satellite communication
d. Magnetics
41. Monopulse technique is used in
a. Radar
b. Radio relay
c. Data communication
d. Fibre-optics
42. HDLC is a term for
a. Data communication protocol
b. Synchronizing pulses
c. Gain control in receivers
d. Error checking
43. A gateway
a. Is a place where radars are connected
b. Permits dissimilar networks to communicate
c. Bifurcates the RF path of a transmitter
d. Is a feeder cable
44. Ethernet is a name of
a. Medium of computer communication
b. Network for computer communication
c. Procedures for computer communication network
d. Software for computer communication
45. If several stations in a network want to use a single channel without interfering with one another, the technique used is called
a. Carrier sense
b. Phantom-freeze
c. Packet switching
d. Multiplexing
46. In a monolithic IC, resistors are formed from
a. Ceramic materials
b. Copper
c. P-type semiconductor
d. Aluminium deposition
47. ICs made by sputtering of materials on a ceramic substrate are called
a. Monolithic b. Hybrid c. Thick film d. Thin film
48. Two coils (inductors) connected in series have a combined inductance of 15mH. When terminals of one of the coils are reversed and connected to the other, the combined inductance is measured to be 9mH. What is the value of mutual inductance
a. 1.5mH b.3mH c.6mH d.12mH
49. If a parallel LC circuit is excited at frequency less than its resonant frequency, the nature of its effective impedance is
a. Resistive b. Inductive c. Capacitive d. None of these of these
50. The wave length of 1 Giga hertz frequency signal is
a. 10cm b. 30cm c. 3cm d. 1cm
51. Which of the following microwave tubes can be considered as broad band devices
a. Magnetrons
b. Klystrons
c. Reflex klystrons
d. Traveling wave tubes[TWT]
No comments:
Post a Comment