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.
| 8001. |
Assertion (A): In India we use CCIR-B standardReason (R): Video signals are frequency modulated. |
| 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» D. A is wrong but R is correct | |
| 8002. |
Household tape recorders use |
| A. | separate motor for each operation |
| B. | only one motor for all operations |
| C. | one motor for capstan and another for take up reel |
| D. | a total of 3 motors |
| Answer» C. one motor for capstan and another for take up reel | |
| 8003. |
A 400 W carrier is modulated to a depth of 75 percent. The total power in modulated wave will be |
| A. | 38.5 W |
| B. | 400 W |
| C. | 512.5 W |
| D. | 615.5 W |
| Answer» D. 615.5 W | |
| 8004. |
A geostationary satellite |
| A. | is located at a height of 358, 00 km |
| B. | appears stationary over earth's magnetic pole |
| C. | is motionless in space but keeps spinning |
| D. | orbits the earth within a 24 hour period |
| Answer» E. | |
| 8005. |
For an ideal 3000 Hz channel, Nyquist rate is |
| A. | 3000 bps |
| B. | 6000 bps |
| C. | 9000 bps |
| D. | 12000 bps |
| Answer» C. 9000 bps | |
| 8006. |
Assertion (A): Electromagnetic waves in free space spread uniformly in all directions from a point sourceReason (R): Free space has no interference or obstacles. |
| 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 | |
| 8007. |
In the FM wave described by equation v = 15 sin (4 x 108 t + 3 sin 1100 t), the maximum frequency deviation is |
| A. | 175 Hz |
| B. | 525 Hz |
| C. | 3 Hz |
| D. | 58.33 Hz |
| Answer» C. 3 Hz | |
| 8008. |
The radar cross-section of a target depends an |
| A. | frequency |
| B. | polarization of incident wave |
| C. | aspect of target |
| D. | all of the above |
| Answer» E. | |
| 8009. |
The Nyquist sampling interval, for the signal sin c (700t) + sin c (5000 t) is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/534-922-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/534-922-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/534-922-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/communication-systems/534-922-4.png"> |
| Answer» D. <img src="/_files/images/electronics-and-communication-engineering/communication-systems/534-922-4.png"> | |
| 8010. |
In case of probability of the message is 1 to 16 then the information will be |
| A. | 16 bits |
| B. | 8 bits |
| C. | 4 bits |
| D. | 2 bits |
| Answer» D. 2 bits | |
| 8011. |
The saving of power in DSB-SC modulated at 80% is |
| A. | NIL |
| B. | 80% |
| C. | 75.76% |
| D. | 50% |
| Answer» D. 50% | |
| 8012. |
In PAL system weighting of R - Y and B - Y signals is done to |
| A. | prevent over modulation on saturated colours |
| B. | prevent under modulation of saturated colours |
| C. | allow over modulation of saturated colours |
| D. | allow under modulation on saturated colours |
| Answer» B. prevent under modulation of saturated colours | |
| 8013. |
In a CD the sampling frequency is nearly |
| A. | half the highest frequency in audio signal |
| B. | equal to highest frequency in audio signal |
| C. | double the highest frequency in audio signal |
| D. | four times the highest frequency in audio signal |
| Answer» D. four times the highest frequency in audio signal | |
| 8014. |
Consider the following statements about loop antenna It is suitable for direction finding applicationIt is a single turn or multiturn coil carrying RF currentThe loop is surrounded by a magnetic field everywhere perpendicular to the loop Which of the above statements are correct? |
| A. | 1 and 2 only |
| B. | 1 only |
| C. | 1, 2, 3 |
| D. | 2 and 3 only |
| Answer» D. 2 and 3 only | |
| 8015. |
Which of the following is present in both TRF receiver and superheterodyne receiver? |
| A. | Detector |
| B. | Mixer |
| C. | IF amplifier |
| D. | Local oscillator |
| Answer» B. Mixer | |
| 8016. |
The modulation index is, if fm = 500 Hz, f = 2.25 kHz |
| A. | 2.25 |
| B. | 4.5 |
| C. | 9 |
| D. | 18 |
| Answer» C. 9 | |
| 8017. |
In PCM, if the number of quantization levels is increased from 4 to 64, then the bandwidth requirement will approximately be increased __________ times. |
| A. | 8 |
| B. | 16 |
| C. | 3 |
| D. | 32 |
| Answer» D. 32 | |
| 8018. |
A tweeter should be fed from the input through a |
| A. | low pass filter |
| B. | high pass filter |
| C. | band pass filter |
| D. | band stop filter |
| Answer» C. band pass filter | |
| 8019. |
24 telephone channels, each band limited to 3.4 kHz are to be time division multiplexed using PCM. If sampling frequency is 10 kHz and number of quantization levels is 128, the required bandwidth of PCM is |
| A. | 1.68 MHz |
| B. | 240 kHz |
| C. | 81.6 kHz |
| D. | 3.072 MHz |
| Answer» B. 240 kHz | |
| 8020. |
Resonant circuits are used in |
| A. | audio amplifiers |
| B. | RF amplifiers |
| C. | both audio and RF amplifiers |
| D. | none of the above |
| Answer» C. both audio and RF amplifiers | |
| 8021. |
Linear diode detector utilizes |
| A. | linear portion of static characteristics of diode |
| B. | linear portion of dynamic characteristic of diode |
| C. | square law portion of dynamic characteristics of diode |
| D. | rectification property of diode |
| Answer» E. | |
| 8022. |
In the equivalent circuit of a moving coil cone type loudspeaker, the mass of the moving system is represented by |
| A. | a resistance |
| B. | a capacitance |
| C. | an inductance |
| D. | a conductance |
| Answer» D. a conductance | |
| 8023. |
The output resistance of a microphone is 20 ohms. It is to feed a line of impedance 320 ohms. To ensure maximum power transfer, the turn ratio of transformer is |
| A. | 16 |
| B. | 256 |
| C. | 2 |
| D. | 4 |
| Answer» E. | |
| 8024. |
Audio cassettes used in household tape recorders have a width of |
| A. | 1" |
| B. | 1/2" |
| C. | 1/4" |
| D. | 1/8" |
| Answer» D. 1/8" | |
| 8025. |
Sound waves are electromagnetic waves. |
| A. | True |
| B. | False |
| Answer» C. | |
| 8026. |
In major diatonic musical scale, an octave is divided into |
| A. | 12 intervals |
| B. | 10 intervals |
| C. | 7 intervals |
| D. | 5 intervals |
| Answer» D. 5 intervals | |
| 8027. |
The bandwidth of DSB suppressed carrier modulation system when the modulating frequency varies between 500 Hz and 5 kHz is |
| A. | 555 kHz |
| B. | 505 kHz |
| C. | 500 kHz |
| D. | 9 kHz |
| Answer» E. | |
| 8028. |
An AM signal and a narrowband FM signal with identical carriers, modulating signals and modulation index of 0.1 are added together. The resultant signal can be closely approximated by |
| A. | Broadband FM |
| B. | SSB with carrier |
| C. | DSB-SC |
| D. | SSB without carrier |
| Answer» C. DSB-SC | |
| 8029. |
The filter circuit for feeding a wooffer has |
| A. | an inductance in series and capacitance in parallel |
| B. | a capacitance in series and an inductance in parallel |
| C. | a resistance in series and an inductance in parallel |
| D. | an inductance in series and a resistance in parallel |
| Answer» B. a capacitance in series and an inductance in parallel | |
| 8030. |
In the equation of M-ary PSK signal (where Ey is symbol energy), M becomes large. Then d will approach |
| A. | 2 |
| B. | infinity |
| C. | zero |
| D. | 1 |
| Answer» D. 1 | |
| 8031. |
The equation v(t) = A cos [ ct + (t)] where A and c are constant and (t) is a function of base signal represents Phase modulationAmplitude modulationAngle modulationFrequency modulation Which of the above are true? |
| A. | 3 only |
| B. | 1, 3 and 4 |
| C. | 1, 2, 3, 4 |
| D. | 3 and 4 only |
| Answer» C. 1, 2, 3, 4 | |
| 8032. |
An FM signal with deviation is passed through mixer. Its frequency is reduced five fold. The deviation in output of mixer is |
| A. | 0.28 |
| B. | |
| C. | 5 |
| D. | very very high |
| Answer» C. 5 | |
| 8033. |
In a TV, studio the function of vision switcher is to |
| A. | edit television programs |
| B. | relay television programs |
| C. | control zoom lens |
| D. | mix audio and video signals |
| Answer» B. relay television programs | |
| 8034. |
The total number of channels allotted for cellular telephone is |
| A. | 666 |
| B. | 333 |
| C. | 221 |
| D. | 111 |
| Answer» B. 333 | |
| 8035. |
To ensure good transient response in audio systems the natural frequencies should be |
| A. | above 40 Hz and below 15 kHz |
| B. | above 40 Hz |
| C. | above 15 kHz |
| D. | below 40 Hz and above 15 kHz |
| Answer» D. below 40 Hz and above 15 kHz | |
| 8036. |
The trapezoidal pattern of figure is obtained when examining an AM wave by an oscilloscope. Modulation factor of the wave is |
| A. | 0.33 |
| B. | 0.5 |
| C. | 2 |
| D. | 1 |
| Answer» C. 2 | |
| 8037. |
Y signal has maximum percentage of |
| A. | red colour |
| B. | blue colour |
| C. | green colour |
| D. | red and blue colours |
| Answer» D. red and blue colours | |
| 8038. |
Consider the following features of monochrome TV Number of lines per picture 625Interlace ratio 2 : 1Aspect ratio 4 : 3Channel bandwidth 8 MHz As regards CCIR system B, which of the above are correct? |
| A. | 1, 2, 3, 4 |
| B. | 1, 2, 3 |
| C. | 1, 2, 4 |
| D. | 2, 3, 4 |
| Answer» C. 1, 2, 4 | |
| 8039. |
The open loop gain of an amplifier is 200. If negative feedback with = 0.2 is used, the closed loop gain will be |
| A. | 200 |
| B. | 40 |
| C. | 4.878 |
| D. | 1.212 |
| Answer» D. 1.212 | |
| 8040. |
The open loop gain of an amplifier is 50 but is likely to change by 20%. If negative feedback with = 0.1 is used, the change in gain will be about |
| A. | 20% |
| B. | 10% |
| C. | 4% |
| D. | 0.05% |
| Answer» D. 0.05% | |
| 8041. |
Audio amplifiers need |
| A. | Bass control |
| B. | Treble control |
| C. | Both Bass and Treble control |
| D. | Either Bass or Treble control |
| Answer» D. Either Bass or Treble control | |
| 8042. |
If the oscillator output is modulated by audio frequencies upto 10 kHz, the frequency range occupied by the side bands will be |
| A. | 711.9 kHz to 712.1 kHz |
| B. | 702 kHz to 722 kHz |
| C. | 692 kHz to 732 kHz |
| D. | 71.2 kHz to 71.20 kHz |
| Answer» C. 692 kHz to 732 kHz | |
| 8043. |
The power to the portable unit of a cordless telephone is provided by |
| A. | pencil cells |
| B. | dry cells |
| C. | rechargeable cells |
| D. | AC mains |
| Answer» D. AC mains | |
| 8044. |
In a AM wave the carrier and one of the side bands is suppressed. If m = 0.5, the percentage saving in power is |
| A. | 50% |
| B. | 83.3% |
| C. | 94.4% |
| D. | 100% |
| Answer» D. 100% | |
| 8045. |
E and H fields are perpendicular to each other. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8046. |
It is found that in a telephone system 60 subscribers initiate calls during a 30 minute interval and the total duration of all the calls is 100 minutes. The load is |
| A. | 2 |
| B. | 3 erlang |
| C. | 3.333 erlang |
| D. | 0.333 erlang |
| Answer» D. 0.333 erlang | |
| 8047. |
Consider the following: A TV receiver antenna should pick up the TV signal and develop maximum voltage from the available strength of signalIt should reject unwanted signalsIt should not suffer from co-channel interferenceIt should have a very narrowband The correct statements are |
| A. | 1 and 2 only |
| B. | 1, 2 and 3 only |
| C. | 1, 2, 3, 4 |
| D. | 2, 3 only |
| Answer» C. 1, 2, 3, 4 | |
| 8048. |
If transmission bandwidth is doubled in FM, SNR is |
| A. | doubled |
| B. | raised four times |
| C. | decreased four times |
| D. | halved |
| Answer» D. halved | |
| 8049. |
In a two stage cascade amplifier, each stage has a gain of 10 dB and noise figure of 10 dB. The overall noise factor is |
| A. | 10 |
| B. | 1.09 |
| C. | 1 |
| D. | 10.9 |
| Answer» E. | |
| 8050. |
Fields are said to be circularly polarised if their magnitudes are |
| A. | equal and they are in phase |
| B. | equal but they differ in phase by 90 |
| C. | unequal and differ in phase by 90 |
| D. | unequal but are in phase |
| Answer» C. unequal and differ in phase by 90 | |