MCQOPTIONS
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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.
| 7901. |
Full duplex operation |
| A. | requires modems at both ends of circuit |
| B. | requires two pairs of cables |
| C. | can transfer data in both directions simultaneously |
| D. | all of the above |
| Answer» E. | |
| 7902. |
In a tape recorder the erase head is |
| A. | engaged during playback but disengaged during recording |
| B. | engaged both during recording and playback |
| C. | disengaged both during recording and playback |
| D. | engaged during recording but disengaged during playback |
| Answer» E. | |
| 7903. |
Consider the following statements as regards advantages of CCD sensors as camera pick up tube High sensitivityGood spectral responseImage lag absent Out of the above which are correct |
| A. | 1, 2, 3 |
| B. | 1, and 2 only |
| C. | 1 and 3 only |
| D. | 2 and 3 only |
| Answer» B. 1, and 2 only | |
| 7904. |
Some desirable features of a computer communication network are It should accept an intended transmission without excessive delayThe data arriving at a receiving point should be processed rapidlyWhen a transmission calls for a response, the delay of response should be minimum. Which of the above are true? |
| A. | 1 and 2 only |
| B. | 1 and 3 only |
| C. | 1, 2, 3 |
| D. | 2 and 3 only |
| Answer» D. 2 and 3 only | |
| 7905. |
Television transmission is by |
| A. | ground waves |
| B. | sky waves |
| C. | space waves |
| D. | all of the above |
| Answer» D. all of the above | |
| 7906. |
In TV signals colour burst is used |
| A. | to maintain colour sequence |
| B. | to ensure I and Q phase correctly |
| C. | to synchronise colours |
| D. | for interlacing of horizontal lines |
| Answer» C. to synchronise colours | |
| 7907. |
The resonant frequency of an RF amplifier is 1 MHz and its bandwidth is 10 kHz. The Q factor will be |
| A. | 10 |
| B. | 100 |
| C. | 0.01 |
| D. | 0.1 |
| Answer» C. 0.01 | |
| 7908. |
Indicate the false statement: If SWR on a transmission line is infinite, the line is terminated in |
| A. | open circuit |
| B. | short circuit |
| C. | pure reactance |
| D. | complex impedance |
| Answer» E. | |
| 7909. |
Loudness control gives |
| A. | high boost to bass and little boost to treble |
| B. | equal boost to bass and treble |
| C. | less boost to bass and more boost to treble |
| D. | less boost to both bass and treble |
| Answer» B. equal boost to bass and treble | |
| 7910. |
A mobile telephone has a range of about |
| A. | 50 km |
| B. | 10 km |
| C. | 1 km |
| D. | 0.1 km |
| Answer» B. 10 km | |
| 7911. |
When energy is fed into open wire transmission line the energy may get dissipated due to |
| A. | radiation |
| B. | conductor heating |
| C. | dielectric heating |
| D. | all of the above |
| Answer» E. | |
| 7912. |
If transmitted power is 75 kW, the field strength at 30 km distance will be about |
| A. | 10 V/m |
| B. | 1 V/m |
| C. | 50 mV/m |
| D. | 2 mV/m |
| Answer» D. 2 mV/m | |
| 7913. |
A Discone antenna is |
| A. | a combination of disk and cone in close approximity |
| B. | a combination of disk and cone at /4 spacing |
| C. | a combination of disk and cone far apart |
| D. | a combination of disk and cone at /2 spacing |
| Answer» B. a combination of disk and cone at /4 spacing | |
| 7914. |
In a two tone AM system the two modulating frequencies are 2000 p and 4000 p rad/sec. If carrier frequency is 2p x 106 rad/sec the frequencies of upper sidebands are |
| A. | 1.002 MHz and 1.004 MHz |
| B. | 1.001 MHz and 1.002 MHz |
| C. | 1.001 MHz and 1.004 MHz |
| D. | 1.002 MHz and 1.008 MHz |
| Answer» C. 1.001 MHz and 1.004 MHz | |
| 7915. |
For a system to be designated as hi-fi, the signal to noise ratio should be at least |
| A. | 25 dB |
| B. | 50 dB |
| C. | 75 dB |
| D. | 100 dB |
| Answer» C. 75 dB | |
| 7916. |
Dolby system of noise reduction divides the total audio spectrum into |
| A. | 8 frequency bands |
| B. | 4 frequency bands |
| C. | 2 frequency bands |
| D. | none of the above |
| Answer» C. 2 frequency bands | |
| 7917. |
In a system an input resistance of 20 kΩ causes a noise voltage of 15 V. If two such input resistances each of 20 kΩ are used in parallel, the total noise voltage will be about |
| A. | 15 V |
| B. | 30 V |
| C. | 7.5 V |
| D. | 10.6 V |
| Answer» E. | |
| 7918. |
A total of 16 equally probable events exist. If it is required to select one out of them, the number of required bits is |
| A. | 2 |
| B. | 4 |
| C. | 3 |
| D. | 5 |
| Answer» C. 3 | |
| 7919. |
Quantizing error occurs in |
| A. | TDM |
| B. | FDM |
| C. | PCM |
| D. | PWD |
| Answer» D. PWD | |
| 7920. |
In audio cassettes the width of each recording track is |
| A. | 5 mm |
| B. | 2.5 mm |
| C. | 1.5 mm |
| D. | 1 mm |
| Answer» C. 1.5 mm | |
| 7921. |
When modulation index of an AM wave is increased from 0.5 to 1, the transmitted power |
| A. | remains the same |
| B. | increases by 25% |
| C. | increases by 33.3% |
| D. | increases by 50% |
| Answer» D. increases by 50% | |
| 7922. |
In a high speed modem the data rate handled is about |
| A. | 1000 bps |
| B. | 5000 bps |
| C. | 20000 bps |
| D. | 50000 bps |
| Answer» C. 20000 bps | |
| 7923. |
The most commonly used transistor amplifier circuit is |
| A. | CB |
| B. | CC |
| C. | CE |
| D. | CE or CC |
| Answer» D. CE or CC | |
| 7924. |
Which of the following is true in a tape recorder? |
| A. | Vow is due to variation in motor speed but flutter is due to some other reason |
| B. | Both vow and flutter are due to variations in motor speed |
| C. | Flutter is due to variation in motor speed but vow is due to some other reason |
| D. | Neither vow nor flutter is due to variation in motor speed |
| Answer» C. Flutter is due to variation in motor speed but vow is due to some other reason | |
| 7925. |
Trinitron is a monochrome picture tube. |
| A. | True |
| B. | False |
| Answer» C. | |
| 7926. |
The number of channels in a stereophonic system is |
| A. | 8 |
| B. | 4 |
| C. | 2 |
| D. | 1 |
| Answer» D. 1 | |
| 7927. |
The first pulse in a TV remote control is |
| A. | start pulse |
| B. | preliminary pulse |
| C. | either start pulse or preliminary pulse |
| D. | erase pulse |
| Answer» C. either start pulse or preliminary pulse | |
| 7928. |
If the ratio of ac to dc load impedance of a diode detector is low, the result will be |
| A. | poor AGC operation |
| B. | poor AF response |
| C. | negative peak clipping |
| D. | diagonal clipping |
| Answer» D. diagonal clipping | |
| 7929. |
A signal x(t) = 100 cos (24p x 103t) is ideally sampled with a sampling period of 50 sec and then passed through an ideal low pass filter with cut off frequency of 15 kHz Which of the following frequencies are present at the filter output? |
| A. | 12 kHz only |
| B. | 8 kHz only |
| C. | 12 kHz and 9 kHz |
| D. | 12 kHz and 8 kHz |
| Answer» E. | |
| 7930. |
A sinusoidal voltage of 2 kV peak value is amplitude modulated to give 20% modulation. The peak value of each side band term is |
| A. | 400 V |
| B. | 200 V |
| C. | 100 V |
| D. | 800 V |
| Answer» C. 100 V | |
| 7931. |
Consider the following reasons for using antenna coupler To prevent illegal radiation of spurious frequenciesTo tune out reactive components of antenna impedanceTo have correct value of load impedance for transmitter. Which of the above are correct? |
| A. | 1, 2, 3 |
| B. | 1, 2 |
| C. | 1 only |
| D. | 2, 3 |
| Answer» B. 1, 2 | |
| 7932. |
An FM signal with a deviation is passed through a mixer, and has its frequency reduced 5 fold. The deviation in the output of the mixer is |
| A. | 5/ |
| B. | Intermediate |
| C. | /5 |
| D. | |
| Answer» E. | |
| 7933. |
Which camera tube has highest dark current? |
| A. | Plumbicon |
| B. | Vidicon |
| C. | Saticon |
| D. | GCD imager |
| Answer» B. Vidicon | |
| 7934. |
If a sound wave has a frequency of 50 Hz, the wavelength is |
| A. | 66 m |
| B. | 6.6 m |
| C. | 0.66 m |
| D. | 0.066 m |
| Answer» C. 0.66 m | |
| 7935. |
Consider the following Generation of SSB signalsDesign of minimum phase type filtersRepresentation of band pass signals Which of the above applications is Hilbert transform used? |
| A. | 1 only |
| B. | 1, 2 and 3 |
| C. | 1, 2 only |
| D. | 1 and 3 |
| Answer» C. 1, 2 only | |
| 7936. |
The dc voltage on plate modulated class C amplifier is 8 kV. If the peak modulating voltage is 4 kV, the peak RF voltage delivered to load is |
| A. | 32 kV |
| B. | 12 kV |
| C. | 0.5 kV |
| D. | 24 kV |
| Answer» E. | |
| 7937. |
The antenna diameter of a radar system is doubled. The maximum range will |
| A. | be doubled |
| B. | become four times |
| C. | be halved |
| D. | decrease to one fourth |
| Answer» B. become four times | |
| 7938. |
Skin depth at 1000 MHz in comparison with that at 500 MHz is |
| A. | 2 |
| B. | <span class="root">2</span> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/511-364-1.png"> |
| D. | 1/2 |
| Answer» D. 1/2 | |
| 7939. |
Which of the following microphones works on the piezoelectric effect? |
| A. | Carbon |
| B. | Condenser |
| C. | Moving coil |
| D. | Crystal |
| Answer» E. | |
| 7940. |
A 200 Hz sound wave is to be transmitted by a 1000 kHz radio wave using frequency modulation. The instantaneous frequency variation will be |
| A. | 100 times a second |
| B. | 200 times a second |
| C. | 400 times a second |
| D. | 1000 times a second |
| Answer» C. 400 times a second | |
| 7941. |
In a TV studios, flying spot scanner is a device for |
| A. | mixing video and audio signals |
| B. | telecasting feature films |
| C. | live telecast of outdoor programs |
| D. | telecast of indoor music programs |
| Answer» C. live telecast of outdoor programs | |
| 7942. |
FSK is a system involving |
| A. | pulse modulation |
| B. | frequency modulation |
| C. | amplitude modulation |
| D. | phase modulation |
| Answer» C. amplitude modulation | |
| 7943. |
The requirements of carrier frequency are |
| A. | precise frequency value |
| B. | low frequency drift |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 7944. |
A device has two resistances 300 &ohm; and 200 &ohm; respectively. The noise voltages due to these two resistance calculated separately are 5.38 V and 4.38 V respectively. When both of them are used together, the noise voltage will be |
| A. | 9.76 V |
| B. | 1 V |
| C. | 23.56 V |
| D. | 6.94 V |
| Answer» E. | |
| 7945. |
The contrast control in colour TV receiver is done by |
| A. | chroma amplifier |
| B. | SAW filter |
| C. | video detector |
| D. | luminance amplifier |
| Answer» E. | |
| 7946. |
Some advantages of optical fibre cables are small diameterImmunity to cross talk and EM interferenceLaser and LED modulation methods lend themselves ideally to digital operation Which of the above are correct? |
| A. | 1 only |
| B. | 1 and 2 |
| C. | 1, 2, 3 |
| D. | 2, 3 |
| Answer» D. 2, 3 | |
| 7947. |
Assertion (A): In standing wave pattern, the nodes and anti nodes are separated by half wave-lengthReason (R): When line is terminated in resistance RL, the standing wave ratio is SWR = Z0/RL or RL/Z0 |
| 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 | |
| 7948. |
The received signal frequency at any time of a super-heterodyne receiver having IF = 456 kHz is 1 MHz. The corresponding image signal is |
| A. | within the medium band |
| B. | outside the medium band |
| C. | depend upon modulation index |
| D. | depends on Modulating frequency |
| Answer» B. outside the medium band | |
| 7949. |
An amplifier has an input resistance of 10 k&ohm; and the noise voltage is 10 V. If two such resistances of 10 k&ohm; each are connected in series at the input, the total noise voltage is about |
| A. | 20 V |
| B. | 5 V |
| C. | 14.14 V |
| D. | 10 V |
| Answer» D. 10 V | |
| 7950. |
A directional microphone gives an output of 0.5 mV whereas an omnidirectional one gives an output of 0.5 V in the same position for the same sound pressure. The directivity of the directional microphone is |
| A. | 120 dB |
| B. | 90 dB |
| C. | 60 dB |
| D. | 30 dB |
| Answer» D. 30 dB | |