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.
| 7951. |
In a colour TV receiver the bandwidth of RF amplifier is |
| A. | exactly equal to channel width |
| B. | a little less than channel width |
| C. | a little more than channel width |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 7952. |
An FM signal with a deviation is passes through the mixer, and has its frequency reduced five fold. The deviation in the output of the mixer is |
| A. | |
| B. | 5 |
| C. | /5 |
| D. | indeterminant |
| Answer» B. 5 | |
| 7953. |
If Eb, the energy per bit of a binary digital signal is 10-6 watt sec. and the one sided power spectral density of the white noise N0 = 10-5 W/Hz, then the output SNR of the matched filter is |
| A. | 26 dB |
| B. | 10 dB |
| C. | 20 dB |
| D. | 13 dB |
| Answer» E. | |
| 7954. |
Consider the following statements about Rhombic antenna It is non resonantIt is a broad band antennaIt is ideally suited for HF transmission Which of the above are correct? |
| A. | 1, 2, 3 |
| B. | 1, 3 only |
| C. | 2, 3 only |
| D. | 1 only |
| Answer» B. 1, 3 only | |
| 7955. |
Assertion (A): A composite video signal has synchronising pulses.Reason (R): It is necessary to synchronise the scanning process in the transmitter and receiver. |
| 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 | |
| 7956. |
A 300 Hz sound wave of intensity 20 dB is transmitted by a 1500 kHz radio wave by frequency modulation. It is seen that instantaneous frequency varies between 1500.2 kHz and 1499.8 kHz, 300 times a second. If the intensity of sound wave is 100 dB. |
| A. | The instantaneous frequency variations will be between 1500.2 and 1499.8 kHz, 1500 times a second |
| B. | The instantaneous frequency variations will be between 1501 and 1499 kHz, 1500 times a second |
| C. | The instantaneous frequency variations will be between 1501 and 1499 kHz, 300 times a second |
| D. | The instantaneous frequency variations will be between 1501 and 1499 kHz, 60 times a second |
| Answer» D. The instantaneous frequency variations will be between 1501 and 1499 kHz, 60 times a second | |
| 7957. |
If the average power of radar transmitters is 2 kW and the peak power of the transmitter is 1000 kW, what will be the duty cycle? |
| A. | 0.002 |
| B. | 0.02 |
| C. | 0.001 |
| D. | 0.01 |
| Answer» B. 0.02 | |
| 7958. |
An analog signal is band limited to B Hz sampled at Nyquist rate and samples are quantized into 4 levels each with probability . The information rate is |
| A. | 4 bits/s |
| B. | B bits/s |
| C. | 4 B bits/s |
| D. | 0.25 B bits/s |
| Answer» D. 0.25 B bits/s | |
| 7959. |
A line has L = 0.8 H/m and C = 32 pF/m. Z0 = |
| A. | 6000 |
| B. | 600 |
| C. | 158 |
| D. | 15.8 |
| Answer» D. 15.8 | |
| 7960. |
A line has standing waves with a voltage maximum of 35 mV and minimum of 17.5 mV VSWR is |
| A. | 2 |
| B. | 4 |
| C. | 0.5 |
| D. | 0.25 |
| Answer» B. 4 | |
| 7961. |
The HV supply to a TV receiver is 25 kV and the total beam current for the three electron guns is 2000 A. The power handled by IHVT is |
| A. | 5W |
| B. | 0.5 W |
| C. | 50 W |
| D. | 500 W |
| Answer» D. 500 W | |
| 7962. |
An RF carrier of 12 kV at 1 MHz is amplitude modulated by 1 kHz signal having peak value of 6 kV. The modulation pattern is seen on CRO screen. The voltage indicated will be |
| A. | 18 kV |
| B. | 1.001 kV |
| C. | 6 kV |
| D. | 36 kV |
| Answer» E. | |
| 7963. |
In push pull amplifier, each transistor conducts for |
| A. | 180 |
| B. | 360 |
| C. | 90 |
| D. | 45 |
| Answer» B. 360 | |
| 7964. |
In the television system in India, each channel is allowed a bandwidth of |
| A. | 20 MHz |
| B. | 12 MHz |
| C. | 7 MHz |
| D. | 3 MHz |
| Answer» D. 3 MHz | |
| 7965. |
In a perfect conductor the resistor noise is |
| A. | maximum |
| B. | zero |
| C. | very high |
| D. | almost infinite |
| Answer» C. very high | |
| 7966. |
A diode detector load consists of 0.01 F capacitor in parallel with a 5 k ohms resistor. The maximum depth of modulation without diagonal clipping at modulating frequency of 1000 Hz and 10 kHz is |
| A. | 0.76, 0.24 |
| B. | 0.95, 0.3 |
| C. | 0.24, 076 |
| D. | 0.3, 0.95 |
| Answer» C. 0.24, 076 | |
| 7967. |
For maximum output the width of air gap of audio head should be |
| A. | equal to wavelength |
| B. | half the wavelength |
| C. | one quarter the wavelength |
| D. | very small as compared to wavelength |
| Answer» C. one quarter the wavelength | |
| 7968. |
An antenna has a resistance of 50 Ω and an equivalent noise resistance of 30 Ω The noise figure in decibels is |
| A. | 1.6 dB |
| B. | 2 dB |
| C. | 3.6 dB |
| D. | 6 dB |
| Answer» C. 3.6 dB | |
| 7969. |
An MTI radar operating at 5 GHz has a PRF of 800 pps. The lowest blind speed is |
| A. | 48 m/s |
| B. | 96 m/s |
| C. | 192 m/s |
| D. | 24 m/s |
| Answer» B. 96 m/s | |
| 7970. |
Telecine equipment in a TV studio consists of |
| A. | projector telecine |
| B. | flying spot telecine |
| C. | digital CCD telecine |
| D. | none of the above |
| Answer» E. | |
| 7971. |
The simplest mixer circuit for public address system uses |
| A. | fixed resistances |
| B. | variable resistances |
| C. | inductances |
| D. | capacitances |
| Answer» C. inductances | |
| 7972. |
A remote control of TV uses a 10 bit word. The maximum number of total commands it can transmit is |
| A. | 64 |
| B. | 256 |
| C. | 512 |
| D. | 1024 |
| Answer» E. | |
| 7973. |
In a TV, the output from RF tuner is about |
| A. | 1 V |
| B. | 1000 V |
| C. | 100 V |
| D. | 0.5 V |
| Answer» C. 100 V | |
| 7974. |
24 telephone channels, each band limited to 3.4 kHz, are to be time division multiplexed by using PCM, calculate the bandwidth of PCM system for 128 quantization levels and an 8 KHz sampling frequency |
| A. | 192 kHz |
| B. | 2 MHz |
| C. | 1.299 MHz |
| D. | 1.54 MHz |
| Answer» E. | |
| 7975. |
Generally a VCR has |
| A. | four stationary video heads |
| B. | two stationary video heads |
| C. | four rotating video heads |
| D. | two rotating video heads |
| Answer» E. | |
| 7976. |
The time required for horizontal blanking is 16% of that for each horizontal line. If horizontal time is 63.5 s, the horizontal blanking time for each line is about |
| A. | 1 s |
| B. | 10 s |
| C. | 100 s |
| D. | none of the above |
| Answer» C. 100 s | |
| 7977. |
When the number of quantising levels is 16 in PCM, the number of pulses in a code group will be |
| A. | 3 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» C. 8 | |
| 7978. |
In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor. |
| A. | 8/6 |
| B. | 12 |
| C. | 16 |
| D. | 8 |
| Answer» D. 8 | |
| 7979. |
For 10 bit PCM system, the signal to quantization noise ratio is 62 dB. If the number of bits is increased by 2, then the signal to quantization noise ratio will |
| A. | increased by 6 dB |
| B. | increased by 12 dB |
| C. | decreased by 6 dB |
| D. | decreased by 12 dB |
| Answer» C. decreased by 6 dB | |
| 7980. |
AM amplifier having noise figure of 20 dB and available power gain of 15 dB is followed by a mixer circuit having noise figure of 9 dB. The overall noise figure as referred to input in dB is |
| A. | 10.44 |
| B. | 11.07 |
| C. | 21.52 |
| D. | 0.63 |
| Answer» B. 11.07 | |
| 7981. |
Which one of the following is non-resonant antenna? |
| A. | Folded dipole |
| B. | Broad side array |
| C. | End fire array |
| D. | Rhombic antenna |
| Answer» E. | |
| 7982. |
The efficiency of using a binary system for selection of 1 out of 13 equally probable events is |
| A. | 100% |
| B. | about 92% |
| C. | about 83% |
| D. | about 71% |
| Answer» B. about 92% | |
| 7983. |
The most suitable method for detecting a modulated signal g(t) = (3 to 6 cos 2pfmt) cos 2pfct is |
| A. | envelope detector |
| B. | synchronous detector |
| C. | ratio detector |
| D. | both a and b |
| Answer» B. synchronous detector | |
| 7984. |
In the television system in India, each frame is scanned |
| A. | 100 times |
| B. | 50 times |
| C. | 20 times |
| D. | 10 times |
| Answer» C. 20 times | |
| 7985. |
Each kilometer of travel in electromagnetic radiation means a time delay of |
| A. | 330 s |
| B. | 33 s |
| C. | 3.3 s |
| D. | 0.33 s |
| Answer» D. 0.33 s | |
| 7986. |
A RADAR can be used to |
| A. | aim a gun at an aircraft |
| B. | to direct guided missiles |
| C. | to search submarines |
| D. | all of the above |
| Answer» E. | |
| 7987. |
In single tone AM modulation, the transmission efficiency for m = 1 is |
| A. | 33.3% |
| B. | 50% |
| C. | 100% |
| D. | 16.65% |
| Answer» B. 50% | |
| 7988. |
A video monitor is exactly similar to TV receiver. |
| A. | True |
| B. | False |
| Answer» C. | |
| 7989. |
When the carrier is unmodulated, a certain transmitter radiates 9 kW when the carrier is sinusoidally modulated the transmitter radiates 10.125 kW. The modulation index will be |
| A. | 0.1 |
| B. | 10.15 |
| C. | 0.4 |
| D. | 0.5 |
| Answer» E. | |
| 7990. |
The video heads, in VCR, feed the other circuit |
| A. | directly windings |
| B. | through a transformer having two rotating windings |
| C. | through a transformer having two stationary windings |
| D. | through a transformer having one stationary and one rotatory winding |
| Answer» E. | |
| 7991. |
A high pulse repetition frequency in a radar |
| A. | increases the maximum range |
| B. | decreases the maximum range |
| C. | has no effect on the maximum range |
| D. | either (a) or (b) depending on other factors |
| Answer» D. either (a) or (b) depending on other factors | |
| 7992. |
Which of the following microphones is the cheapest? |
| A. | Moving coil |
| B. | Condenser |
| C. | Ribbon |
| D. | Carbon |
| Answer» E. | |
| 7993. |
In PCM, the biggest disadvantage as compared to AM is |
| A. | larger bandwidth |
| B. | larger noise |
| C. | inability to handle analog signals |
| D. | incompatibility with time division multiplex systems |
| Answer» B. larger noise | |
| 7994. |
Kell factor is about |
| A. | 5 |
| B. | 3 |
| C. | 0.7 |
| D. | 0.2 |
| Answer» D. 0.2 | |
| 7995. |
TV signal strength when expressed in dB m has the reference of |
| A. | 10 V/m |
| B. | 5 V/m |
| C. | 2 V/m |
| D. | 1 V/m |
| Answer» E. | |
| 7996. |
A sinusoidal voltage amplitude modulates a carrier of peak value 5 kV. Each side band has an amplitude of 500 V. The modulation index is |
| A. | 0.1 |
| B. | 0.2 |
| C. | 0.4 |
| D. | 0.8 |
| Answer» C. 0.4 | |
| 7997. |
For a bit rate of 8 kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are |
| A. | 16 kHz and 20 kHz |
| B. | 20 kHz and 32 kHz |
| C. | 20 kHz and 40 kHz |
| D. | 32 kHz and 40 kHz |
| Answer» E. | |
| 7998. |
If luminance signal Y = 0.3 R + 0.59 G + 0.11 B, the hue of R - Y colour is |
| A. | 0.7 R - 0.59 G - 0.11 B |
| B. | - 0.7 R + 0.59 G + 0.11 B |
| C. | 1.3 R - 0.59 G - 0.11 B |
| D. | none of the above |
| Answer» B. - 0.7 R + 0.59 G + 0.11 B | |
| 7999. |
CATV stands for |
| A. | Common Antenna Television |
| B. | Community Antenna Television |
| C. | Cable Antenna Television |
| D. | Channel Antenna Television |
| Answer» C. Cable Antenna Television | |
| 8000. |
Trap circuits used in video IF amplifier of colour TV are |
| A. | High Q, LC resonant circuit |
| B. | Low Q, LC resonant circuit |
| C. | High Q, RLC resonant circuit |
| D. | Low Q, RLC resonant circuit |
| Answer» B. Low Q, LC resonant circuit | |