MCQOPTIONS
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MCQOPTIONS
This section includes 1362 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1301. |
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. | |
| 1302. |
While AM has __________ frequencies, FM has __________ number of sidebands. |
| A. | 2, 3 |
| B. | 3, 3 |
| C. | 3, 5 |
| D. | 3, infinite |
| Answer» E. | |
| 1303. |
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 | |
| 1304. |
Assertion (A): EM waves are attenuated as they travel outward from a sourceReason (R): Both field intensity and power density follow inverse square law. |
| 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 | |
| 1305. |
If f is frequency and d is distance, path attenuation a between isotropic antennas is given by |
| A. | a = 33 + 20 log f + 20 log d |
| B. | a = 100 + 33 log f + 33 log d |
| Answer» B. a = 100 + 33 log f + 33 log d | |
| 1306. |
A signal having uniformly distributed amplitude in the interval (- V to + V) is to be encoded using PCM with uniform quantization. The signal to quantization noise ratio is determined by |
| A. | dynamic range of signal |
| B. | sampling rate |
| C. | number of quantizing levels |
| D. | power spectrum of signal |
| Answer» C. number of quantizing levels | |
| 1307. |
Radio broadcasts are generally |
| A. | amplitude modulation |
| B. | frequency modulation |
| C. | both amplitude and frequency modulation |
| D. | neither amplitude nor frequency modulation |
| Answer» C. both amplitude and frequency modulation | |
| 1308. |
Switching systems |
| A. | are limited to small data networks |
| B. | require additional lines |
| C. | are not used in data system |
| D. | improve the efficiency of data transfer |
| Answer» E. | |
| 1309. |
In a perfect conductor the resistor noise is |
| A. | maximum |
| B. | zero |
| C. | very high |
| D. | almost infinite |
| Answer» C. very high | |
| 1310. |
Which of the following is a digital modulation technique? |
| A. | PCM |
| B. | PSK |
| C. | DM |
| D. | All |
| Answer» E. | |
| 1311. |
A better SNR can be obtained in a PCM by |
| A. | increasing sampling rate above Nyquist rate |
| B. | decreasing the code bits |
| C. | reducing channel bandwidth |
| D. | increasing Quantization levels |
| Answer» E. | |
| 1312. |
In push button type telephone set, pressing a button generates |
| A. | one frequency |
| B. | two high frequencies |
| C. | two low frequencies |
| D. | one low frequency and one high frequency |
| Answer» E. | |
| 1313. |
Reception through space wave is limited to line of sight distance. |
| A. | 1 |
| B. | |
| C. | 16 Mbps |
| D. | 100 Mbps |
| Answer» B. | |
| 1314. |
In the spectrum of an FM wave |
| A. | When modulation index is large, carrier frequency disappears |
| B. | carrier frequency cannot disappear |
| C. | amplitude of any side band depends on modulation index |
| D. | the total number of side bands depend on modulation index |
| Answer» D. the total number of side bands depend on modulation index | |
| 1315. |
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 | |
| 1316. |
Entropy gives |
| A. | measure of Uncertainty |
| B. | rate of Information |
| C. | average information |
| D. | probability of Information |
| Answer» B. rate of Information | |
| 1317. |
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 | |
| 1318. |
A 1000 kHz carrier is simultaneously modulated with 300 Hz, 800 Hz and 2 kHz audio sine waves. Which of the following frequency is least likely to be present in the output? |
| A. | 1002 kHz |
| B. | 1000 kHz |
| C. | 999.2 kHz |
| D. | 998.0 kHz |
| Answer» C. 999.2 kHz | |
| 1319. |
Push pull amplifier is |
| A. | class B |
| B. | class A |
| C. | class C |
| D. | Class A or Class C |
| Answer» B. class A | |
| 1320. |
If the radiated power of AM transmitter is 10 kW, the power in the carrier for modulation index of 0.6 is nearly. |
| A. | 8.24 kW |
| B. | 8.47 kW |
| C. | 9.26 kW |
| D. | 9.6 kW |
| Answer» C. 9.26 kW | |
| 1321. |
In high power AM transmission, modulation is done at |
| A. | IF stage |
| B. | buffer stage |
| C. | RF stage |
| D. | oscillator stage |
| Answer» E. | |
| 1322. |
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 | |
| 1323. |
In tape recorder erase head is active during recording. |
| A. | 1 |
| B. | |
| C. | Ribbon |
| D. | Condenser |
| Answer» B. | |
| 1324. |
In PCM the amplitude levels are transmitted in a 7 unit code. Sampling frequency is 10 kHz. The bandwidth should be |
| A. | 5 kHz |
| B. | 35 kHz |
| C. | 70 kHz |
| D. | 5 MHz |
| Answer» C. 70 kHz | |
| 1325. |
Which of the following is an indirect way of generating FM? |
| A. | Armstrong modulator |
| B. | Varactor diode modulator |
| C. | Reactance FET modulator |
| D. | Reactance bipolar transistor |
| Answer» B. Varactor diode modulator | |
| 1326. |
Which of the following is the main advantage of PCM system? |
| A. | Lower noise |
| B. | Lower power |
| C. | Lower bandwidth |
| D. | All of the above |
| Answer» B. Lower power | |
| 1327. |
For attenuation of high frequencies we should use |
| A. | shunt capacitance |
| B. | series capacitance |
| C. | inductance |
| D. | resistance |
| Answer» B. series capacitance | |
| 1328. |
Consider the following types of distortions in diode detectors Distortion is caused due to the reason that dc and ac load impedances are unequalDistortion is caused because ac load impedance has a reactive component at high audio frequenciesAudio frequency diode current is less than dc current Which of the above are true? |
| A. | 1, 2 and 3 |
| B. | 1 and 2 |
| C. | 1 and 3 |
| D. | 2 and 3 |
| Answer» C. 1 and 3 | |
| 1329. |
A Discone antenna is |
| A. | a combination of disk and cone in close approximity |
| B. | a combination of disk and cone at λ/4 spacing |
| C. | a combination of disk and cone far apart |
| D. | a combination of disk and cone at λ/2 spacing |
| Answer» B. a combination of disk and cone at Œª/4 spacing | |
| 1330. |
Chrome signals in PAL colour television system consist of |
| A. | R - Y and B - Y signal |
| B. | V and U signals |
| C. | I and Q signals |
| D. | R - Y and G - Y signals |
| Answer» C. I and Q signals | |
| 1331. |
In a satellite system circular polarization is to be obtained. The antenna used is |
| A. | parabolic |
| B. | horn |
| C. | log periodic |
| D. | helical |
| Answer» E. | |
| 1332. |
As the frequency increases, the absorption of ground wave by earth's surface |
| A. | decreases |
| B. | increases |
| C. | remains the same |
| D. | either (a) or (c) |
| Answer» C. remains the same | |
| 1333. |
A modem is classified as low speed if data rate handled is |
| A. | upto 100 bps |
| B. | upto 250 bps |
| C. | upto 400 bps |
| D. | upto 600 bps |
| Answer» E. | |
| 1334. |
Which of the following form of angle modulation in this? If e = 10 sin(108 t + 3 sin 104 t) |
| A. | AM |
| B. | FM |
| C. | AM or FM |
| D. | AM or PCM |
| Answer» C. AM or FM | |
| 1335. |
A generator is feeding power to a transmission line of characteristic impedance Z0. The line is terminated in impedance ZL. Standing waves will be set up if |
| A. | ZL = Z0 |
| B. | ZL < Z0 |
| C. | ZL > Z0 |
| D. | both (b) and (c) |
| Answer» E. | |
| 1336. |
A woofer 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» B. high pass filter | |
| 1337. |
The block diagram of AM transmitter in which high level modulation is used as shown in figure. The block X could be |
| A. | audio power amplifier |
| B. | buffer RF amplifier |
| C. | compressor amplifier |
| D. | none of the above |
| Answer» C. compressor amplifier | |
| 1338. |
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. | |
| 1339. |
Which of following digital modulation technique? |
| A. | ASK |
| B. | FSK |
| C. | PSK |
| D. | All |
| Answer» E. | |
| 1340. |
A telephone channel requires a bandwidth of about |
| A. | 1 kHz |
| B. | 3 kHz |
| C. | 10 kHz |
| D. | 50 kHz |
| Answer» C. 10 kHz | |
| 1341. |
At a given probability of error, binary coherent FSK is interior to binary coherent PSK by |
| A. | 6 dB |
| B. | 3 dB |
| C. | 2 dB |
| D. | 0 dB |
| Answer» C. 2 dB | |
| 1342. |
In radar systems PRF stands for |
| A. | Power Return Factor |
| B. | Pulse Return Factor |
| C. | Pulse Repetition Frequency |
| D. | Pulse Response Factor |
| Answer» D. Pulse Response Factor | |
| 1343. |
Transit time is considered as significant at |
| A. | HF |
| B. | MF |
| C. | LF |
| D. | all of the above |
| Answer» E. | |
| 1344. |
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 | |
| 1345. |
It is desired that transmission line and load should match for a range of frequencies. The best method is |
| A. | to use a balun |
| B. | to use a single stub of adjustable position |
| C. | to use a double stub |
| D. | to use a broad band amplifier |
| Answer» D. to use a broad band amplifier | |
| 1346. |
A receiver has poor selectivity. It will also have poor |
| A. | sensitivity |
| B. | double spotting |
| C. | blocking |
| D. | diversity reception |
| Answer» D. diversity reception | |
| 1347. |
Which of the following is taken as reference antenna for directive gain? |
| A. | Half wave dipole |
| B. | Elementary doublet |
| C. | Isotropic |
| D. | Infinitesimal dipole |
| Answer» D. Infinitesimal dipole | |
| 1348. |
A bit synchronizer regenerates at the receiver a clock waveform which is |
| A. | synchronous with original clock waveform |
| B. | out of phase by 180° with original clock waveform |
| C. | out of phase by 90° with the original clock waveform |
| D. | none of the above |
| Answer» B. out of phase by 180¬∞ with original clock waveform | |
| 1349. |
Consider the following test signal patterns RampGrillGrey shadesSine pulsePicture line up generating equipment Which of the above are used in TV studios? |
| A. | All |
| B. | 1, 2 and 3 only |
| C. | 1, 2 and 5 only |
| D. | 2, 3, 4 and 5 only |
| Answer» B. 1, 2 and 3 only | |
| 1350. |
Which of the following microphones has bidirectional feature? |
| A. | Moving coil |
| B. | Ribbon |
| C. | Condenser |
| D. | Carbon |
| Answer» C. Condenser | |