|
#1
July 3rd, 2014, 09:01 AM
| |||
| |||
|
Can you please give me the past year question papers of Bharat Electronics Limited of probationary engineer job for ECE? As you want to get the past year question papers of Bharat Electronics Limited of probationary engineer job for ECE so here is the information of the same for you: BEL Placement Paper 2 (Technical-Electronics-IInd) 1. Resistivity of silicon in ohms cm. is approx. equal to a. 50 b. 1012 c. 230k d. 10-6 2. Rsistivity ofGermanium in ohms cm. is approx. equal to a. 50 b. 10-12 c. 50k d. 10-6 3. The number of free electrons/cubic cm intrinsic Germanium at room temperature is approx. equal to a. 1.5*1010 b. 2.5*1013 c. 1000 d. 5*106 4. The number of free electrons/cubic cm of intrinsic silicon at room temperature is approx. equal to a. 1.5*1010 b. 2.5*1013 c. 10000 d. 5*106 5. The forbidden energy gap for silicon is a. 1.1eV b. 067eV c. 0.97eV d. 1.7eV 6. The forbidden energy gap for Germanium is a. 1.1eV b. 067eV c. 0.97eV d. 1.7eV 7. N type material is formed by the addition of the following (penta valent )atom in n to semiconductor material a. Antimony b. Arsenic c. Phosphorous d. Any of the above 8. P type material is formed by the addition of the following [Trivalent] atom tn to semiconductor material a. Boron b. Gallium c. Indium d. Any of the above 9. Impurity atoms that produces N type material by its addition in semiconductor is called a. Donar b. Acceptor c. Conductor d. Insulator 10. Impurity atoms that produces P type material by its addition in semiconductor is called a. Donar b. Acceptor c. Conductor d. Insulator 11. Dynamic resistance of a diode Rd is if voltage changes is DVd and the current change is D Id a. D Vd / D Id b. D Id / D Vd c. 1 / DVd d. 1 / D Id 12. Point contact diodes are preferred at very high frequency, because of its low junction a. Capacitance and inductance b. Inductance c. Capacitance 13. Identify the circuit given below a. AND gate b. OR gate c. Rectifier d. NOR gate 14. Identify the circuit given below a. AND gate b. OR gate c. Rectifier d. NOR gate 15. DC value of a Half wave rectifier with Em as the peak value of the input is a. 0.318Em b. 0.418Em c. 0.518Em d. 0.618Em 16. Change in Zener voltage of 10V at 100o C if temperature co-efficient is 0.072%o C as a. 0.54 V b. 0.74 V c. 0.64 V d. 0.14 V 17. If Tc is th e% temperature co of / oC and Vz as zener voltage and T as change in temperature then the change in zener voltage is a. b. c. 100. Vz. Tc DT d. None of these of the above 18. PIV for a full wave rectifier, if Em is the peak voltage is a. Em b. 1.5Em c. 0.636Em d. 2Em 19. Schottky Barrier diodes becomes important at a. DC level operation b. Low frequency operation c. High frequency operation d. None of these 20. Clamping network is the one that will clamp the signal to a a. Different peak value b. Different DC level c. Different polarity level d. Different RMS level 21. Clipping network is the one that will clip a portion of the a. Input signal without distorting the remaining portion b. Input signal with distorting the remaining portion c. Any of the above d. None of these 22. Transition capacitance Ct of a Varicap diode with Knee voltage Vt, reverse voltage Vr and K, the constant based on semiconductor material and the construction technique & N dependent on type of junction is given by a. 1 / K (Vt + Vr)N/2 b. 1 / K (Vt + Vr)N c. K / (Vt + Vr)N d. K / (Vt + Vr)1/N 23. Ct = K / (Vt + Vr)N where Vt Knee voltage, Vr reverse voltage, K manufacturing dependent constant and N dependent on type of junction, for alloy junction the value of N is a. 1/3 b. 2/3 c. 1/2 d. 1/4 24. Ct = K / (Vt + Vr)N where Vt Knee voltage, Vr reverse voltage, K manufacturing dependent constant and N dependent on type of junction, for diffused junction the value of N is a. 1/3 b. 2/3 c. 1/2 d. 1/4 25. In JFET, the drain current Id is given by (Idss drain – source saturation current Vgs – Gate – source voltage, Vp the pinch off voltage) a. Idss[1 – Vp/Vgs] b. Idss(1 – Vgs/Vp)2 c. Idss[1 – Vgs/Vp) d. Idss(1 – Vgs/Vp)3/2 26. The shadow mask in colour tube is used to a. Reduce X-Ray emission b. Ensure each beam hits its own dots c. Increase screen brightness d. Provide degaussing for the screen 27. Indicate which of the following signal is not transmitted in colour TV a. Y b. Q c. R d. I 28. Another name for horizontal retrace in TV receiver is the a. Ringing b. Burst c. Damper d. Fly back 29. Another name for the colour sync in the colour TV system a. Ringing b. Burst c. Damper d. Fly back 30. The HV anode supply for a picture tube of a TV receiver is generated in the a. Mains transformer b. Vertical output stage c. Horizontal output stage d. Horizontal oscillator 31. The output of vertical amplifier is a. Direct current b. Amplified vertical sync pulse c. A saw tooth voltage d. A saw tooth current 32. In a transistor if Alpha = 0.98, current gain is equal to a. 29 b. 59 c. 69 d. 49 33. The active region in the common emitter configuration means a. Both collector and emitter junction is reverse biased b. The collector junction is forward biased and emitter junction c. The collector junction is reverse biased and emitter junction is forwared biased d. Both collector & emitter junction are forward biased 34. The saturation region in the common emitter configuration means that a. Both collector & emitter junction are reverse biased b. The collector junction is forward biased and emitter junction c. The collector junction is reverse biased and emitter junction is forwared biased d. Both collector & emitter junction are forward biased 35. The % of Red, Green & Blue in 100% White Y is given by a. 30%, 59%, 11% b. 50%, 30%, 11% c. 30%, 11%, 50% d. 33.3%, 33.5%, 38.3% 36. Equalizing pulse width, if H is the Horizontal sync rate a. 0.64 H b. 0.07 H c. 0.04 H d. 0.16 H 37. In a simple RC network the bandwidth is equal to a. 1/2 p RC b. RC / 2 c. 2 C / p R d. 2 p / RC 38. The time constant of a RC network is given by a. RC b. C/R c. R/C d. None of these 39. First zero crossing of pulse frequency spectrum occurs at if d is the pulse width, T is the pulse repetition rate a. 1/d b. d/T c. T/d d. T 40. The distortion less output characteristic of a network means a. Constant amplitude and linear phase shift over frequency b. Linear phase shift and amplitude need not be constant c. Any amplitude and phase d. None of these 41. Single sideband means suppressed a. Carrier b. Carrier and one side band c. One side band d. None of these 42. In an amplitude modulated signal, lower side band frequency is equal to (if the carrier frequency is fc and modulation frequency is fm) a. fm + fc b. fc – fm c. fm r fc d. fc / fm 43. Modulation index of the frequency modulation depends on a. Amplitude & frequency of the modulation signal b. Frequency and amplitude of carrier signal c. Carrier frequency d. None of these 44. The BW of the narrow band FM if modulating frequency is fm a. 3 r fm b. 2 r fm c. 2.5 r fm d. 10 r fm 45. Reactance tube modulator is known for a. FM b. AM c. PPM d. PAM 46. Bandwidth and rise time product is a. 0.35 b. 0.45 c. 0.30 d. 0.49 47. Energy gap, Lg, for Germanium at room temp [300o K] is a. 0.72eV b. 1.1eV c. 1.53eV d. 0.2eV 48. Volt equivalent of temperature VT, at 116o K is a. 0.11V b. 0.01V c. 1.16V d. 0.1V 49. Reverse saturation current of a Ge.diode is in the range of a. mA b. uA c. nA d. pA 50. Cut-in voltage V for silicon is approximately a. 0.2V b. 0.6V c. 0.9V d. 1.1V 51. Every 10o C rise in temp. the reverse saturation current a. Doubles b. Halves c. Triples d. No change 52. Hall effect with reference to Metal or Semiconductor carrying a current I is placed in a transverse magnetic field B, an electric field E is induced in a. Parallel to B b. Perpendicular to I c. Perpendicular to both B & I d. Perpendicular to B 53. 1 eV (electron volt) is equal to: a. 1.9 r 10-20 J b. 1.6 r 10-19 J c. 1.6 r 10-20 J d. 1.16 r 10-19 J 54. Donar impurity is having a valency of: a. 2 b. 3 c. 4 d. 5 55. Acceptor impurity is having a valency of a. 2 b. 3 c. 4 d. 5 56. Electron volt arises from the fact that if any electron falls through a potential of 1 volt, its kinetic energy will a. Decrease, & potential energy will increase b. Increase & potential energy decrease c. Be unaltered & potential energy decreases d. Increase & potential energy increase 57. Hole is created in a semiconductor material if one of following impurities are added a. Antimony b. Arsenic c. Indium d. Phosphorus 58. Excess electron is created by a. Boran b. Gallium c. Indium d. Arsenic 59. A snubber circuit is used across the SCR to protect against a. The di/dt of the anode current b. The dv/dt turn on c. L.di/dt of load inductance d. None of these 60. Germanium has the valency of a. 2 b. 3 c. 4 d. 5 61. Silicon has the valency of a. 2 b. 3 c. 4 d. 5 62. Hole acts as a free charge carrier of polarity a. Negative b. Positive c. Neutral d. None of these 63. Burst signal in NTSC system is 8 cycles of the frequency of a. Colour sub carrier b. Picture carrier c. Sound carrier d. None of these 64. Colour sub carrier reference burst is superimposed on the a. Back porch of the each horizontal sync pulse b. Front porch of the each horizontal sync pulse c. Front porch of the each vertical sync pulse d. Back porch of the each vertical sync pulse 65. The law of mass action with reference to semiconductor technology states that the product of free negative & positive concentration is a constant and a. Independent of amount of donor and acceptor doping b. Dependent on amount of donor and independent of the amount acceptor impurity doping c. Depend on amount of both donor & acceptor impurity doping d. None of these 66. The snubber circuit used across SCR is a simple a. R-L network b. RLC network c. LC network d. RC network 67. To limit the rate of rise of SCR anode current a small a. Inductor is inserted in cathode circuit b. Inductor is inserted in anode circuit c. Capacitor is inserted in anode circuit d. Capacitor is inserted in cathode circuit 68. Torque developed by a DC servo motor is proportional to the a. Product of power and time b. Product of armature current and back emf c. Armature voltage and armature current d. Field voltage and field current 69. Proportional Integral control a. Reduces steady state error but reduces the forward gain b. Increases the forward gain and reduces the steady state error c. Increases the steady state error and increases the forward gain d. None of these 70. Increasing the servo bandwidth: a. Improves signal to noise ratio b. Improves speed response and lowers signal to noise ratio c. Improves power output d. None of these 71. Notch filter is a. Low pass filter b. High pass filter c. Narrow stop band filter d. Narrow pass band filter 72. In TV Receivers the Electron beam deflection method used is a. Electro static b. Electro magnetic c. Magnetic d. All the above 73. In a line of sight communication the maximum range R in miles between the receiver antenna and transmitter antenna of height H in feet is approximately a. R = 1.93 ÖH b. R = 1.23 ÖH c. R = 1.53 ÖH d. R = 2.03 ÖH 74. In wavelength of the 60 MHz carrier frequency is a. 10 metres b. 15 metres c. 5 metres d. 2.5 metres 75. In standard TV receiving antenna the dipole element is a. 0.5 of the wave length b. 0.25 of the wave length c. 1.5 of the wave length d. 1.0 of the wave length 76. The characteristics of FET are similar to: a. Triode b. Tertode c. Pentode d. Diode 77. Charge coupled device is an array of capacitors whose structure is similar to: a. Shift register b. Flip-flop c. NAND gate d. Amplifier 78. Operational amplifier characteristics are which of the following: a. Infinite gain b. Infinite input impedance c. Output impedance is zero d. All of the above 79. The typical value of the open loop gain in dB of an amplifier at DC with no feedback is: a. 90 to 100 b. 80 to 90 c. 0 to 50 d. 50 to 70 80. The 3 dB band width means the frequency at which a. The open loop voltage gain reduced to 0.707 b. The open loop gain reduced to unity c. Maximum voltage of a signal is without distortion d. It is a medium wave band width of radio receiver 81. Rise time of an amplifier is defined as time required a. To change from 0 to 100 % of its final value b. To change from 0 to 50 % of its final value c. To change from 10 to 90 % of its final value d. To change from 10 to 100 % of its final value 82. High speed amplifier design emphasized on a. Extremely small bandwidth b. Very slow response c. Unity gain bandwidth after 10 MHz d. None of these 83. Tuned amplifier having the frequency range between a. 150 KHz – 50 MHz b. 100 Hz – 100 KHz c. 100 KHz – 120 KHz d. 50 MHz – 100 MHz 84. The resonance frequency of a tuned circuit made up of R, L, C is given by a. 1/2 pÖLC b. 2 pÖLC c. 2 p / ÖLC d. ÖLC / 2 85. The voltage follower can be obtained using operational amplifier a. Without any feedback b. Series parallel feedback of unity c. Parallel feedback d. Series feedback 86. Fidelity of the amplifier is when a. It is a linear amplifier b. It does not add or subtract any spectral components c. It amplifier each component by the same amount d. All of the above 87. What would be the output when two input sine waves of frequency 50 KHz and 100 KHz passed through an amplifier in the medium signal a. 50 KHz and 100 KHz b. 100 KHz and 200 KHz c. 50 KHz and 150 KHz d. All of the above 88. The important application of Schmitt trigger is a. To convert slowly varying input voltage to abrupt voltage change b. To convert abruptly varying input voltage into slowly varying output c. To change the frequency of the input d. None of these 89. Meaning of decoding is a. Binary addition b. Data transmission c. Demultiplexing d. Storage of binary information 90. Approximately how many number of gates are incorporated in SSL chip a. 12 b. 100 c. Excess of 100 d. Excess of 1000 91. The circuit diagram represents which one of the following a. Half adder b. Full adder c. Exor gate d. AND gate 92. Flip flop cannot be called as a. Bistable multivibrator b. 1 Bit memory unit c. latch d. combinational circuit 93. The important use of low pass filter in power supply is a. To get the regulation in the output voltage b. To filter out the ripple frequency c. To increase the current rating d. To convert AC into DC 94. Binary equivalent of the decimal number 145 is a. 10010001 b. 1001011 c. 1010001 d. 1100010 95. In which of the following gate the output will be high when all the maintained at high level a. NOR b. AND c. NAND d. EXOR 96. Which of the following definition is true in the De Morgan’s theorem a. Multiplication symbols are replaced by addition symbol b. Addition symbols are replaced by Multiplication symbol c. Each of the terms are expressed in the complementary form d. All of the above 97. 8421/BCD code fro a decimal number 149 is a. 0001 0100 1001 b. 10010101 c. 10101001 d. None of these 98. Combinational circuit are mainly characterized by a. Output depends upon the previous state & presents state b. Output depends upon the input at that particular instant c. Output depends upon the presents state & the clock state d. Output does not depends upon the input at all 99. A flip flop is defined as a. A bistable device with two complementary outputs b. It is memory element c. It will respond to input and it is a basic memory element d. All of the above 100. Four bit code is called a. Nibble b. Byte c. Word d. Register Answer:- 1. c2. a3. a4. b5. a6. b7. d8. d9. a10. b11. a12. c13. b14. a15. a16. a17. a18. d 19. c20. b21. a22. c23. c24. a25. b26. b27. c28. d29. b30. c31. d32. d33. c34. d35. a36. c37. a38. d39. a40. a41. b42. b43. a44. b45. b46. a47. a48. b49. b50. b51. a52. c53. b54. b55. b56. b57. c58. d59. b60. c61. c62. b63. a64. a65. a66. d67. b68. b69. a70. b71. c72. c73. b74. c75. a76. c77. a78. d79. d80. a81. c82. c83. a84. a85. b86. d87. a88. a89. c90. a91. a92. d93. b94. a95. b96. d97. a98. b99. d100.a Technical-Electronics 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 Last edited by Anuj Bhola; October 23rd, 2019 at 12:33 PM. |
|
#2
July 4th, 2014, 09:53 AM
| |||
| |||
| Re: Past year question papers of Bharat Electronics Limited of probationary engineer job for ECE
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] 52. Which family of the following integrated circuits has the highest speed a. DTL b. ECL c. TTL d.CMOS 53. The most important feature of CMOS family of ICs is a. High speed b. Small size c. Low power consumption d. Low input impedance 54. What is the resolution of 8 bit A/D converter if its full scale voltage is 10v a. 0.02v b. 0.01 c. 0.039v d. 0.078v 55. What value of resistance is to be used in LSB of 4 bit weighted ladder D/A converter if MSB has 10 kW resistor a. 160k b. 80k c. 240k d. 100k 56. The pulse width of a radar transmitter is 0.6m sec. and the pulse repetition rate is 700 Hz. The average power measured is 420 watts. What is the peak power a. 100KW b. 420KW c. 1MW d. None of these 57. The device used for isolating the transmitter and receiver in a radar system is called a. Diplexer b. Duplexer c. Directional coupler d. None of these 58. “Baud” is a. Total No. of bits/sec in each character b. Reciprocal of shortest signal element in a character c. Duration of a character in data transmission d. None of these 59. The advantage of Totem pole output stage in TTL ICs is a. Low output impedance b. Can sink more current c. Oscillations avoided d. None of these 60. The capacitance value of a varactor is controlled by a. A reverse voltage applied to it b. A series resistance c. Varying its supply voltage d. Current through the device 61. Electron volt is equivalent to a. 3.8 * 10-20 erg b. 1.602 * 10-12 erg c. 1.602 * 10-18 erg d. 1.602 * 10-16 erg 62. The kinetic energy of photo electrons emitted by a photo sensitive surface depends on a. Intensity of the incident radiation b. Wavelength of the incident radiation c. Angle of incident of radiation d. Surface conditions of the surface 63. Flux is expressed in radio-metric system in a. Lumens b. Photons c. Watts d. Candles 64. In a three-phase bridge rectifier circuit, the ripple frequency is a. Same as line frequency b. Twice the line frequency c. Thrice the line frequency d. Six times the line frequency 65. Energy stored in a capacitor as a function of voltage is given by a. CV2 b. 1V2/2C c. ½ CV2 d. 1V/2C 66. The operational amplifier used in analog computers have usually open loop flat gain approximately upto a. 1MHz b. 100MHz c. 10MHz d. 0.1MHz 67. An oscillator of 350 MHz is fed with a pulse of rise time 2 n sec. The rise time of the displayed waveform is approximately a. 1 n sec b. 2.2 n sec c. 2.0 n sec d. 1.7 n sec 68. A radar transmits a peak power of 100 KW with pulse width of 1 m sec and a pulse repetition rate of 100 KHz. The average output power of the radar is a. 100KW b.10KW c. 1000KW d. 50KW 69. The incremental inductance in a coil is due to a. Saturation b. Superimposed DC c. Mutual inductance d. Change of frequency 70. Microwave tube based on velocity modulation principle is a. Klystron b. Magnetron c. Light house tube d. Traveling wave tube 71. Noise output from the receiver decreases uniformly with noise side band frequency for a. Frequency modulation b. Amplitude modulation c. Pulse amplitude modulation d. None of these 72. In amplitude modulation the maximum permissible modulation index is a. Unity b. 100 c. infinity d. None of these 73. In frequency modulation the maximum permissible modulation index is a. Unity b. 50 c.1000 d. no limit 74. In FM transmission and reception, the pre-emphasis and de-emphasis are used to improve the a. Signal to noise ratio b. Frequency response of the receiver c. Frequency response of the transmitter d. The sensitivity of the transmitter 75. De-emphasis network uses the combination of a. R-L b. R-C c. R-L-C d. Transformer 76. The usage of micro sec for defining emphasis is a standard practice but this micro sec definition means a. 3 dB point of the network means b. mid point of the network response c. roll off the network response d. the stop band ripple of the network response 77. Delayed AGC is applied a. For all singal strength b. For singal strength exceeding a specified limit c. For low singal strength d. For FM receiver 78. Selectivity means a. Bandwidth b. Gain c. Modulation index d. None of these 79. Narrow bandwidth broadcast reduces a. The quality and noise b. Quality alone c. Noise alone d. Quality and intelligibility 80. Squelch means keeping the receiver a. ON in the absence of carrier b. OFF in the absence of carrier c. To remove AGC d. Increase the AGC 81. Let Z be the series impedance and Y be the shunt admittance of the transmission line, then the characteristic impedance a. ÖZY b.ÖY/Z c. ÖZ/Y d.All the above 82. Noise figure of an amplifier is defined as a. Input SNR output SNR b. Input SNR / output SNR c. Output SNR / input SNR d. Input SNR / gain 83. A broadcast radio transmitter radiates 10 KW power when modulation is 60%. Its carrier power will be a. 8.47KW b.8.92KW c. 8.31KW d.10.00KW 84. In AM transmission antenna current is 8 Ampere at zero modulation indexes but increased to 8.93 Ampere when modulated on single sine wave. Then the % of modulation is approximately a. 70.1% b. 80.1% c. 65.1% d. 10.0% 85. In AM transmission antenna current is 8 Ampere at zero modulation index. At 80% modulation index the antenna current will be a. 10.00A b. 8.72A c. 9.19A d. 9.79A 86. If two sine waves are amplitude modulated with modulation index m1 and m2, the effective modulation index is a. Ö m12/m22 b. Ö m1 m2 c. Ö m12+m22 d. Ö m22/m12 87. If it is transmitted current and Ic is transmitter current at zero modulation index and the transmitted current at modulation index of m will a. It = Ic Ö[1+m] b. It = Ic Ö[1+m2] c. It = Ic Ö[1+m/22] d. It = IcÖ1+m2 88. If Rr is the radiation resistance and Rd is the lumped resistance, then the antenna efficiency is given as – a. (Rr - Rd) / (Rr + Rd) b. (Rr + Rd) / (Rr – Rd) c. Rr / (Rr + Rd) d. Rd / (Rr + Rd) 89. In end fire array, the current a. Magnitude and phase in each element is the same b. Magnitude is the same but phase is different in each element c. Magnitude is different but no phase difference in each element d. Magnitude and phase are different in each element 90. In a board side array, the current a. Magnitude and phase in each element is the same b. Magnitude is the same but phase is different c. Magnitude is different but no phase difference in each element d. Magnitude and phase are different in each element 91. Beam width of the 2 metre paraboloid reflector at 6 GHz is a. 4.5o b. 9.25o c. 3.5o d. 7.75o 92. The cut of wave length for TE m, n mode is in a wave guide of dimension a*b is a. 2/Ö(m/a)2 +(n/b)2 b. 2Ö [m/a]2 + [n/b]2 c. Ö(m/a)2 + (n/b)2 /2 d. Ö [m/a]2 + [n/b]2 93. For the standard rectangular waveguide dimension of 4*2 cm the off wavelength for TM11 mode is approximately a. 1.788cm b. 3.576cm c. 1.682cm d. 2.546cm 94. In IMPATT diode, the voltage and current are a. In phase b. Out off phase by 90o c. Out off phase by 180o d. None of these of the above 95. Which of the following statement is true a. Tunnel diode & IMPATT diode are negative resistance devices b. Tunnel diode is positive resistance device and the IMPATT diode is negative resistance device c. Tunnel diode is negative resistance device and the IMPATT diode is positive resistance device d. None of these of the above 96. In a SSB modulation system with 100% modulation index the power saving will be a. 5/6 of carrier power b. 2/8 of carrier power c. 5/12 of the carrier power d. ½ of the carrier power 97. In SSB modulation the modulation index is increased from 0.5 to 1.0, then the power will be increased by a. 2 times b. 4 times c. 16 times d. 32 times 98. 900 rpm is equal to a. 94.2 rad/sec b. 47.1 rad/sec c. 188.4 rad/sec d. 16.72 rad/sec 99. Darlington pair is used to a. Increase the voltage gain b. Increase the current gain c. Decrease voltage gain d. Decrease current gain 100. The transfer function of the system shown is a. G(s) / {1 + H(s)} b. G(s) H(s) / {1 + G(s) H(s)} c. G(s) / {1 + G(s) H(s)} d. G(s) / G(s) H(s) Electronics-I Answers 1. c2. a3. a4. c5. a6. b7. b8. b9. b10. d11. c12. b13. b14. d15. c16. a17. c18. d19. c20. b21. d22. d23. c24. b25. b26. d27. c28. b29. d30. c31. d32. a33. b34. c35. c36. d37. c38. c39. a40. a41. a42. a43. b44. b45. d46. c47. d48. a49. b50. b51. d52. b 53. c54. c55. b56. c57. b58. b59. a60. a61. b62. b63. a64. b65. c66. d67. c68. b 69. d70. a71. a72. a73. b74. a75. b76. a77. b78. a79. a80. b81. c82. b83. a84. a 85. c86. c87. c88. c89. b90. a91. c92. a93. b94. c95. a96. a97. b98. b99. b100. c Contact Details: Bharat Electronic Limited Sahibabad, Industrial Area, Site-4, Bharat Nagar, Industrial Area, Ghaziabad, Uttar Pradesh 201102 India Map Location: |
| |