MCQOPTIONS
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MCQOPTIONS
This section includes 10 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.
| 1. |
Industrial noise exists in a frequency range of |
| A. | 10 – 700 MHz |
| B. | 1 – 800 MHz |
| C. | 1 – 600 MHz |
| D. | 20 – 50 MHz |
| Answer» D. 20 – 50 MHz | |
| 2. |
An unwanted signal that enters the transmitted signal which cannot be controlled is called as: |
| A. | Modulated signal |
| B. | Carrier Signal |
| C. | Modulating Signal |
| D. | Noise Signal |
| Answer» E. | |
| 3. |
An antenna pointing in a certain direction has a noise temperature of 50 K. The ambient temperature is 290 K. The antenna is connected to a pre-amplifier that has a noise figure of 2 dB and an available gain of 40 dB over an effective bandwidth of 12 MHz. The effective input noise temperature Te for the amplifier and the noise power Pao at the output of the preamplifier, respectively, are |
| A. | Te = 169.36 K and Pao = 3.73×10-10 W |
| B. | Te = 170.8 K and Pao = 4.56×10-10 W |
| C. | Te = 182.5 K and Pao = 3.85×10-10 W |
| D. | Te = 160.62 K and Pao = 4.6×10-10 W |
| Answer» B. Te = 170.8 K and Pao = 4.56×10-10 W | |
| 4. |
For identical total transmitted power, the ratio of S / N for wideband FM to S / N of DSB-AM (with ma = 1) is:(Given fm = 15 kHz & frequency deviation = ± 75 kHz) |
| A. | 112.5 |
| B. | 300 |
| C. | 75 |
| D. | 450 |
| Answer» B. 300 | |
| 5. |
A communication channel disturbed by additive white Gaussian noise has a bandwidth of 4 KHz and SNR of 15. The highest transmission rate that such channel can support (ink-bits/sec) is |
| A. | 16 |
| B. | 1.6 |
| C. | 3.2 |
| D. | 60 |
| Answer» B. 1.6 | |
| 6. |
Distortion factor is also known as: |
| A. | noise factor |
| B. | fundamental distortion |
| C. | harmonic distortion |
| D. | total harmonic distortion |
| Answer» E. | |
| 7. |
A system has a receiver noise resistance of 50 Ohm. It is connected to an antenna with an input resistance of 50 Ohm. Calculate the noise figure of the system. |
| A. | 1 |
| B. | 2 |
| C. | 50 |
| D. | 101 |
| Answer» C. 50 | |
| 8. |
Gain and NF of a single-stage amplifier are 10 dB and 3 dB respectively. When two such amplifiers cascaded then gain and NF of the cascaded amplifier will be? |
| A. | Gain : 20 dB, NF : 3.2 dB |
| B. | Gain : 20 dB, NF : 6.0 dB |
| C. | Gain : 13 dB, NF : 3.6 dB |
| D. | Gain : 13 dB, NF : 6.7 dB |
| Answer» B. Gain : 20 dB, NF : 6.0 dB | |
| 9. |
For the 2N338 transistor, the manufacturer specifies P max = 100 mW at 25°C free air temperature and the maximum junction temperature, Tj max = 125°. Its thermal resistance is |
| A. | 10° C/W |
| B. | 100° C/W |
| C. | 1000° C/W |
| D. | 10,000° C/W |
| Answer» D. 10,000° C/W | |
| 10. |
A 1 mW video signal having a bandwidth of 100 MHz is transmitted to a receiver through a cable that has 40 dB loss. If the effective one-sided noise spectral density at the receiver is 10-20 Watt/Hz, then the signal-to-noise at the receiver is |
| A. | 50 dB |
| B. | 30 dB |
| C. | 40 dB |
| D. | 60 dB |
| Answer» B. 30 dB | |