MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The service area of a TV transmitter is a little beyond radio horizon. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2. |
A radio frequency signal contains the following three frequencies : 850 kHz; 865 kHz and 875 kHz In order to amplify this signal, which of the following amplifier should be selected? |
| A. | Push pull amplifier |
| B. | Wideband amplifier |
| C. | Audio frequency amplifier |
| D. | Tuned voltage amplifier |
| Answer» E. | |
| 3. |
Bit is a unit of |
| A. | entropy |
| B. | information |
| C. | channel capacity |
| D. | rate of information |
| Answer» C. channel capacity | |
| 4. |
In pulse transmitter the ratio of time on to time off is called |
| A. | efficiency |
| B. | duty cycle |
| C. | base |
| D. | bandwidth |
| Answer» C. base | |
| 5. |
In figure the output v(t) is |
| A. | phase modulated signal |
| B. | amplitude modulated signal |
| C. | frequency modulated signal |
| D. | none of the above |
| Answer» D. none of the above | |
| 6. |
A MASER is a |
| A. | low noise device |
| B. | high noise device |
| C. | medium noise device |
| D. | may be either high or medium noise device |
| Answer» B. high noise device | |
| 7. |
Transit time is considered as significant at |
| A. | HF |
| B. | MF |
| C. | LF |
| D. | all of the above |
| Answer» E. | |
| 8. |
In a colour TV receiver, AGC adjusts the gain of |
| A. | RF stage only |
| B. | IF stage only |
| C. | RF stage and one or two IF stages |
| D. | none of the above |
| Answer» D. none of the above | |
| 9. |
In VCR the luminance signal is recorded by |
| A. | frequency modulation |
| B. | phase modulation |
| C. | amplitude modulation |
| D. | direct recording |
| Answer» B. phase modulation | |
| 10. |
Assertion (A): In digital communication data is coded prior to being transferred.Reason (R): A number of codes for digital data processing are available. |
| A. | Both A and R are correct and R is correct explanation of A |
| B. | Both A and R are correct but R is not correct explanation of A |
| C. | A is correct but R is wrong |
| D. | A is wrong but R is correct |
| Answer» C. A is correct but R is wrong | |
| 11. |
In FM modulation pre-emphasis is done for |
| A. | high frequency components |
| B. | low frequency components |
| C. | middle frequency components |
| D. | both (a) and (b) |
| Answer» B. low frequency components | |
| 12. |
c(t) and m(t) are used to generate an AM signal. The modulation index of the generated AM signal is 0.5 then the quantity is |
| A. | 1/2 |
| B. | 1/4 |
| C. | 1/3 |
| D. | 1/8 |
| Answer» E. | |
| 13. |
High intermediate frequency in a superheterodyne receiver |
| A. | higher than |
| B. | lower than |
| C. | equal to |
| D. | not comparable to |
| Answer» B. lower than | |
| 14. |
In FSK no synchronous carrier is needed at the receiver |
| A. | true |
| B. | false |
| C. | depend on distance |
| D. | none |
| Answer» C. depend on distance | |
| 15. |
In AM, if modulation index is more than 100%, then |
| A. | bandwidth increases |
| B. | the wave gets distorted |
| C. | power of the wave increases |
| D. | efficiency of transmission increases |
| Answer» C. power of the wave increases | |
| 16. |
The constellation diagram of a modem has four states as shown in the figure given below. What is the bit rate of this modem? |
| A. | Two times its band rate |
| B. | Four times its band rate |
| C. | Same as band rate |
| D. | Sufficient information is not given to give the answer |
| Answer» B. Four times its band rate | |
| 17. |
When the modulating frequency is doubled, the modulation index is halved and the modulating voltage remains constant. The modulation system is |
| A. | FM |
| B. | AM |
| C. | phase modulation |
| D. | none of the above |
| Answer» B. AM | |
| 18. |
Vividh Bharti programme is transmitted in |
| A. | short wave |
| B. | medium frequency |
| C. | all of the above |
| D. | none of the above |
| Answer» D. none of the above | |
| 19. |
The width of air gap on recording head in a tape recorder is about |
| A. | 6 micron |
| B. | 3 micron |
| C. | 1 micron |
| D. | 25 micron |
| Answer» B. 3 micron | |
| 20. |
In a stereo tape recorder the speed of the tape is |
| A. | 38 m/s |
| B. | 19 m/s |
| C. | 9.5 m/s |
| D. | 4.75 m/s |
| Answer» E. | |
| 21. |
Which of the following refers to SSB suppressed carrier amplitude modulated system? |
| A. | A3E |
| B. | H3E |
| C. | J3E |
| D. | C3F |
| Answer» D. C3F | |
| 22. |
Present day stereophonic systems have |
| A. | only CD playback facility |
| B. | only tape playback facility |
| C. | both CD and tape playback facilities along with radio |
| D. | none of the above |
| Answer» D. none of the above | |
| 23. |
If e = 10 sin(108 t + 3 sin 104 t) then carrier frequency is |
| A. | 0.159 MHz |
| B. | 1.59 MHz |
| C. | 15.9 MHz |
| D. | 159 MHz |
| Answer» D. 159 MHz | |
| 24. |
RF choke used for suppressing interference in TV is generally |
| A. | honey comb wound coil |
| B. | iron core coil |
| C. | single layer coil |
| D. | multilayer coil |
| Answer» C. single layer coil | |
| 25. |
Indicate the false statement: To combat noise |
| A. | reduce signalling rate |
| B. | increase transmitted power |
| C. | use redundancy |
| D. | increase channel bandwidth |
| Answer» E. | |
| 26. |
Thermal noise is independent of |
| A. | temperature |
| B. | bandwidth |
| C. | centre frequency |
| D. | Boltzmann constant |
| Answer» D. Boltzmann constant | |
| 27. |
The frequency at which the piezoelectric effect occurs is primarily determined by |
| A. | the weight of the crystal |
| B. | thickness of the crystal |
| C. | length of the crystal |
| D. | gain structure of the crystal |
| Answer» C. length of the crystal | |
| 28. |
Audio and video signals are called modulating waves. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 29. |
In home tape recorders the tape width is 2 inches. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 30. |
The decorative lighting works on the principle of |
| A. | periodic switching on and off |
| B. | special inverter |
| C. | rectifier |
| D. | motor |
| Answer» B. special inverter | |
| 31. |
In an oscillator crystal, the parallel resonant frequency is |
| A. | equal to |
| B. | higher than |
| C. | less than |
| D. | series resonant frequency |
| Answer» B. higher than | |
| 32. |
The highest modulating frequency typically used in AM systems is |
| A. | 1 kHz |
| B. | 5 kHz |
| C. | 20 kHz |
| D. | 50 kHz |
| Answer» C. 20 kHz | |
| 33. |
The line of sight communication requires the transmit and receive antennas to face each other. If the transmit antenna is vertically polarized, for best reception to the receive antenna should be |
| A. | horizontally polarized |
| B. | vertically polarized |
| C. | at 45 within respect to horizontal polarization |
| D. | at 45 with respect to vertical polarization |
| Answer» B. vertically polarized | |
| 34. |
Which of the following statement regarding the advantages of the phase discriminator over the slope detector is false? |
| A. | Better linearity |
| B. | Fewer tuned circuits |
| C. | Much easier alignment |
| D. | Greater limiting |
| Answer» B. Fewer tuned circuits | |
| 35. |
The maximum range of a radar is proportional to |
| A. | square root of peak transmitted pulse power |
| B. | fourth root of peak transmitted pulse power |
| C. | peak transmitted pulse power |
| D. | none of the above |
| Answer» C. peak transmitted pulse power | |
| 36. |
The bandwidth of FM for Commercial Purpose is |
| A. | 88 - 108 MHz |
| B. | 85 - 110 MHz |
| C. | 90 - 110 MHz |
| D. | infinite Range |
| Answer» B. 85 - 110 MHz | |
| 37. |
In FM, the frequency deviation is |
| A. | always constant |
| B. | directly proportional to modulating frequency |
| C. | inversely proportional to modulating frequency |
| D. | proportional to amplitude of modulating signal |
| Answer» E. | |
| 38. |
Speech amplifiers are usually operated as |
| A. | class A |
| B. | classes AB |
| C. | class B |
| D. | class C |
| Answer» B. classes AB | |
| 39. |
In MF range, increasing the transmitter power |
| A. | increases the range of transmitter |
| B. | does not increase the range of transmitter because propagation is limited by tilt |
| C. | decreases the range of transmitter because propagation is limited by tilt |
| D. | increases the range of transmitter because propagation is through space waves |
| Answer» C. decreases the range of transmitter because propagation is limited by tilt | |
| 40. |
SSB-SC stands for |
| A. | Single Side Band-Suppressed Carrier |
| B. | Single Side Band-Synchronous Carrier |
| C. | Synchronous Side Band-Suppressed Carrier |
| D. | Synchronous Side Band-Self Carrier |
| Answer» B. Single Side Band-Synchronous Carrier | |
| 41. |
The most frequent users of long distance VLF transmission is |
| A. | ship communication |
| B. | radio broadcasting |
| C. | TV broadcasting |
| D. | telephone and telegraph |
| Answer» B. radio broadcasting | |
| 42. |
BFO stands for |
| A. | Beat Frequency Oscillator |
| B. | Broad Frequency Oscillator |
| C. | Blocking Frequency Oscillator |
| D. | Ballistic Frequency Oscillator |
| Answer» B. Broad Frequency Oscillator | |
| 43. |
A lens has a hyperfocal distance of 7.5 m. It is focused at 7.5 m. Then |
| A. | all objects from 7.5 m to infinity will appear in focus |
| B. | all objects from 3.75 m to infinity will appear in focus |
| C. | all objects from 0 to 7.5 m will appear in focus |
| D. | all objects from 0 to 3.75 m will appear in focus |
| Answer» C. all objects from 0 to 7.5 m will appear in focus | |
| 44. |
In which frequency range is the noise figure in a transistor independent of frequency |
| A. | intermediate frequencies |
| B. | high frequency |
| C. | low frequencies |
| D. | both low and high frequencies |
| Answer» B. high frequency | |
| 45. |
The frequency tolerance for the RF carrier in the standard AM radio broadcast band is |
| A. | zero |
| B. | +20 Hz |
| C. | +1000 Hz |
| D. | +25 Hz |
| Answer» B. +20 Hz | |
| 46. |
Which of the following is likely to be associated with FM radio broadcasting? |
| A. | 90 Hz |
| B. | 90 kHz |
| C. | 900 kHz |
| D. | 90 MHz |
| Answer» E. | |
| 47. |
In a 4-ary FSK, the frequencies are separated by fs. Then they are |
| A. | in phase |
| B. | in phase opposition |
| C. | orthogonal |
| D. | none of the above |
| Answer» D. none of the above | |
| 48. |
In cell communication, cell stands for |
| A. | Geographical Area |
| B. | Battery |
| C. | Location |
| D. | No meaning |
| Answer» B. Battery | |
| 49. |
In which of the following frequency bands are the standard AM radio broadcast stations? |
| A. | MF |
| B. | HF |
| C. | VHF |
| D. | UHF |
| Answer» E. | |
| 50. |
If carrier is modulated by a digital bit stream having one of the possible phases of 0 , 90 , 180 , and 270 , then modulation is called |
| A. | BPSK |
| B. | QPSK |
| C. | QAM |
| D. | MSK |
| Answer» C. QAM | |