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MCQOPTIONS
This section includes 9294 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 8951. |
As compared to AM, FM requires |
| A. | narrow channel |
| B. | same channel |
| C. | 2 to 3 times as large channel |
| D. | 7 to 15 times as large channel |
| Answer» E. | |
| 8952. |
Capture effect occurs in |
| A. | AM |
| B. | FM |
| C. | PCM |
| D. | QAM |
| Answer» C. PCM | |
| 8953. |
The power consumption of a present day colour TV receiver is about |
| A. | 8 W |
| B. | 80 W |
| C. | 200 W |
| D. | 400 W |
| Answer» C. 200 W | |
| 8954. |
Consider the following differences between QPSK and MSK The side lobes in MSK are relatively much smaller in comparison to the main lobeThe spectrum of MSK has a main centre lobe which is 1.5 times as wide as the main lobe of QPSKThe waveforms of both MSK and QPSK exhibit phase continuity Which of the above statements are correct? |
| A. | 1 only |
| B. | 1 and 2 only |
| C. | 1, 2 and 3 |
| D. | 2 and 3 only |
| Answer» C. 1, 2 and 3 | |
| 8955. |
As per Hartley law |
| A. | redundancy is essential |
| B. | it is necessary to use only binary codes |
| C. | maximum rate of information transmission depends on the channel bandwidth |
| D. | the maximum rate of information depends on depth of modulation |
| Answer» D. the maximum rate of information depends on depth of modulation | |
| 8956. |
In tape recorders the hissing noise is due to irregularities in magnetic coating on tape. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8957. |
Waves travel on each of the line configurations in figure. In which case would the radiation be maximum |
| A. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/521-585-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/521-585-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/521-585-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/521-585-4.png"> |
| Answer» E. | |
| 8958. |
The speeds used in recording audio programs in house hold recorders are |
| A. | 38 cm/s and 9.5 cm/s |
| B. | 38 cm/s and 19 cm/s |
| C. | 9.5 cm/s and 4.75 cm/s |
| D. | 38 cm/s and 4.75 cm/s |
| Answer» D. 38 cm/s and 4.75 cm/s | |
| 8959. |
Assertion (A): In AM carrier component remains constant in amplitude and frequency.Reason (R): In AM the two side bands are images of each other. |
| 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 | |
| 8960. |
The main advantage of TDM over FDM is |
| A. | TDM requires more bandwidth than FDM |
| B. | less complicated in hardware than FDM |
| C. | better SNR |
| D. | required filter |
| Answer» D. required filter | |
| 8961. |
In FM reception, amplitude disturbances due to static change |
| A. | reduce the signal frequencies |
| B. | increase the signal frequencies |
| C. | disturb the signal frequencies |
| D. | do not affect the signal frequencies |
| Answer» E. | |
| 8962. |
A broadcast radio transmitter radiates 5 kW when the modulation percentage is 60. How much of this is carrier power? |
| A. | 6.66 kW |
| B. | 5 kW |
| C. | 4.9 kW |
| D. | 4.23 kW |
| Answer» E. | |
| 8963. |
For a resistance of about 15 k&ohm; operating in a frequency range of a few MHz, the noise voltage is in the range of |
| A. | a few V |
| B. | about 100 V |
| C. | a few V |
| D. | a few volts |
| Answer» B. about 100 V | |
| 8964. |
In a 50 cm TV tube, a path difference of 2 km between direct wave and interfering wave would mean a displacement between main image and ghost image equal to |
| A. | 0.3 cm |
| B. | 3 cm |
| C. | 6 cm |
| D. | 9 cm |
| Answer» B. 3 cm | |
| 8965. |
In a colour TV receiver, the sound intercarrier IF is generated in |
| A. | video detector |
| B. | video IF amplifier |
| C. | tuner mixer stage |
| D. | limiter stage |
| Answer» B. video IF amplifier | |
| 8966. |
In a pulsed RADAR, the transmitter is connected to the antenna |
| A. | during pulse interval |
| B. | during interval between pulses |
| C. | all the time |
| D. | only during a fraction of pulse interval |
| Answer» B. during interval between pulses | |
| 8967. |
In a colour TV receiver, PAL Dematrix consists of |
| A. | chroma detector to separate the three primary colours |
| B. | delay line and PAL matrix to give U and V signals |
| C. | delay line and PAL matrix to give RGB colours |
| D. | none of the above |
| Answer» C. delay line and PAL matrix to give RGB colours | |
| 8968. |
In a CD, the depth and width of each pit is |
| A. | 0.5 m each |
| B. | 0.5 m and 1 mm respectively |
| C. | 1 m and 0.5 mm respectively |
| D. | 1 m each |
| Answer» D. 1 m each | |
| 8969. |
A monostable multivibrator is used to generate PWM because it can |
| A. | differentiator |
| B. | integrator |
| C. | voltage-to-frequency converter |
| D. | generate pulses |
| Answer» E. | |
| 8970. |
Which of the following is not necessarily the advantage of SSB over double sideband, full carrier AM? |
| A. | The signal is more noise resistant |
| B. | More channel space is available |
| C. | Transmitter circuits must be more stable, given better reception |
| D. | Considerably less power is required for the same signal strength |
| Answer» D. Considerably less power is required for the same signal strength | |
| 8971. |
Consider the following statements in amplitude modulation The harmonic and intermodulation distortion may occur in audio and RF amplifiersThe sum and difference frequencies are present in the output of mixerThe diode detector has audio frequencies in its outputA balanced modulator cannot produce an AM with suppressed carrier Which of the above are true? |
| A. | 1, 2, 3, 4 |
| B. | 1, 2, 3 |
| C. | 1, 2 |
| D. | 3, 4 |
| Answer» C. 1, 2 | |
| 8972. |
A resistor R is in parallel with capacitance C. The rms noise voltage of resistor in the equivalent circuit can be written as |
| A. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/502-139-1.png"> |
| B. | <i>k</i> |
| C. | TC |
| D. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/502-139-2.png"> |
| E. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/502-139-3.png"> |
| Answer» B. <i>k</i> | |
| 8973. |
Assertion (A): In angle modulation the transmitted amplitude is constant.Reason (R): Angle modulation has good immunity to noise and interference. |
| 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 | |
| 8974. |
On modulating a carrier of frequency fc by an audio signal fs, the following components has resulted: fc, fc + fs and fc - fs What is this type of modulation likely to be? |
| A. | Amplitude modulation (DSB) |
| B. | Single sideband modulation |
| C. | Frequency modulation only |
| D. | Amplitude modulation or frequency modulation |
| Answer» B. Single sideband modulation | |
| 8975. |
A signal m(t) = 5 cos 2p 100 t frequency modulates a carrier. The resulting FM signal is 10 cos {(2p 105 t) + 15 sin (2p 100 t)} The approximate bandwidth of the FM would be |
| A. | 0.1 kHz |
| B. | 6 kHz |
| C. | 3.2 kHz |
| D. | 100 kHz |
| Answer» E. | |
| 8976. |
Strength of space wave is not dependent on distance. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8977. |
A 1000 kHz carrier is simultaneously modulated with 300 Hz, 800 Hz and 2 kHz audio sine waves. The frequencies present in the output will be |
| A. | 998 kHz and 1002 kHz |
| B. | 998 kHz, 999.2 kHz, 1000.8 kHz, 1002.0 kHz |
| C. | 998 kHz, 999.2 kHz, 999.7 kHz, 1000.3 kHz, 1000.8 kHz and 1000.2 kHz |
| D. | none of the above |
| Answer» D. none of the above | |
| 8978. |
Which wave is also called surface wave? |
| A. | Ground wave |
| B. | Sky wave |
| C. | Space wave |
| D. | Both (b) and (c) |
| Answer» B. Sky wave | |
| 8979. |
ADM stands for |
| A. | Angle Delta Modulation |
| B. | Angle Digital Modulation |
| C. | Adaptive Delta Modulation |
| D. | Adaptive Digital Modulation |
| Answer» D. Adaptive Digital Modulation | |
| 8980. |
Which of the following is correct (FDM means Frequency Division Multiplexing and TDM means Time Division Multiplexing)? |
| A. | FDM requires lower bandwidth but TDM has more noise immunity |
| B. | FDM has more noise immunity and requires lower bandwidth than TDM |
| C. | FDM requires channel synchronization while TDM has more noise immunity |
| D. | FDM requires more multiplexing while TDM requires band pass filter |
| Answer» D. FDM requires more multiplexing while TDM requires band pass filter | |
| 8981. |
The maximum permissible distance between two samples of a 10 kHz signal |
| A. | 100 sec |
| B. | 50 sec |
| C. | 10 sec |
| D. | none |
| Answer» C. 10 sec | |
| 8982. |
Consider the following applications/ advantages of radar beacons navigationtarget identificationaccurate tracking of enemy targetslarge increase in maximum range Which of the above are correct? |
| A. | 1, 2, 3, 4 |
| B. | 1, 2, 4 |
| C. | 1, 2 |
| D. | 2, 3, 4 |
| Answer» C. 1, 2 | |
| 8983. |
Some possible functions of AGC in a TV receiver are To increase gain for weak signalsTo decrease gain for strong signalsTo change the contrast when we switch from one channel to otherTo reduce flutter Which of the above are correct? |
| A. | 1, 2, 3, 4 |
| B. | 1, 2, 4 |
| C. | 1, 2, 3 |
| D. | 2, 3, 4 |
| Answer» C. 1, 2, 3 | |
| 8984. |
In a certain '12 channel TDM' system it is found that channel no. 3 and channel no. 8 are connected to the same input signal. This technique |
| A. | wastes the channel capacity |
| B. | takes care of different sampling rate |
| C. | is required when different bandwidth signals are to be transmitted |
| D. | reduces noise |
| Answer» C. is required when different bandwidth signals are to be transmitted | |
| 8985. |
The signal plate of vidicon tube is coated with tin oxide. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8986. |
In telephone systems, load is expressed in the unit of |
| A. | erlangs |
| B. | decibels |
| C. | bells |
| D. | watts |
| Answer» B. decibels | |
| 8987. |
Which of the following can be used to convert PPM into PWM? |
| A. | Integrator |
| B. | Astable multivibrator |
| C. | Bistable multivibrator |
| D. | Monostable multivibrator |
| Answer» D. Monostable multivibrator | |
| 8988. |
Assertion (A): In FM all power amplifiers can be operated in class C Reason (R): FM is a constant amplitude modulation system. |
| 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» B. Both A and R are correct but R is not correct explanation of A | |
| 8989. |
In radar system which of the following is called A scope |
| A. | deflection modulation of CRT |
| B. | intensity modulation of CRT |
| C. | computer display |
| D. | none of the above |
| Answer» B. intensity modulation of CRT | |
| 8990. |
In a CD the channel separation is |
| A. | 1 m |
| B. | 1.6 m |
| C. | 2.5 m |
| D. | 4 m |
| Answer» C. 2.5 m | |
| 8991. |
The unit for luminous energy is |
| A. | lumens/sec |
| B. | lumens/m |
| C. | <sup>2</sup> |
| D. | lumen-sec |
| E. | lumen/m |
| Answer» D. lumen-sec | |
| 8992. |
The IF bandwidth of a radar receiver is inversely proportional to |
| A. | pulse interval |
| B. | pulse width |
| C. | PRF |
| D. | none of the above |
| Answer» C. PRF | |
| 8993. |
In VHS format diameter of head drum is about |
| A. | 1 m |
| B. | 20 cm |
| C. | 6 cm |
| D. | 1 cm |
| Answer» D. 1 cm | |
| 8994. |
While AM has __________ frequencies, FM has __________ number of sidebands. |
| A. | 2, 3 |
| B. | 3, 3 |
| C. | 3, 5 |
| D. | 3, infinite |
| Answer» E. | |
| 8995. |
The correct sequence of subsystem in an FM receiver is |
| A. | mixer, RF amplifier, limiter, IF amplifier, discriminator, audio amplifier |
| B. | RF amplifier, mixer, IF amplifier, limiter, discriminator, audio amplifier |
| C. | RF amplifier, mixer, limiter, discriminator, IF amplifier, audio amplifier |
| D. | mixer, IF amplifier, limiter, audio amplifier, discriminator |
| Answer» C. RF amplifier, mixer, limiter, discriminator, IF amplifier, audio amplifier | |
| 8996. |
The primary colours are |
| A. | blue and green |
| B. | blue and red |
| C. | red and green |
| D. | blue, red and green |
| Answer» E. | |
| 8997. |
A wave is frequency modulated with an index of 0.1 and its frequency is multiplied by 8 times, the modulation index is |
| A. | not changed |
| B. | decreased 8 times |
| C. | increased 4 times |
| D. | increased 8 times |
| Answer» B. decreased 8 times | |
| 8998. |
Short circuited stubs are preferred to O.C stubs because |
| A. | O.C stubs are incapable of giving full range of reactances |
| B. | O.C stubs are liable to radiate |
| C. | O.C stubs are difficult to make and connect |
| D. | none of the above |
| Answer» C. O.C stubs are difficult to make and connect | |
| 8999. |
Assertion (A): The unit of telephone traffic measurement is erlang.Reason (R): International circuits for communication are fitted with echo suppressors. |
| 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 | |
| 9000. |
In a single sideband suppressed carrier AM system, the modulation index is changed from 0 to 1, the power content of the signal |
| A. | will be quarter |
| B. | will be doubled |
| C. | will increase by 50 percent |
| D. | will increase by 25 percent |
| Answer» D. will increase by 25 percent | |