MCQOPTIONS
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MCQOPTIONS
This section includes 69 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Calculate the effective earth’s radius if the surface refractivity is 301.$? |
| A. | 8493 km |
| B. | 8493 mmi |
| C. | 6370 km |
| D. | 6370 mi |
| Answer» B. 8493 mmi | |
| 52. |
If the duration of the radar transmitted pulse, on a particular range of operation, is increased, the required bandwidth of the receiver’s IF amplifiers? |
| A. | Must remain as before |
| B. | Must be increased |
| C. | May be decreased |
| D. | Must be doubled |
| Answer» D. Must be doubled | |
| 53. |
The maximum usable range of the usual radar set (on any particular range setting) is determined by? |
| A. | The width of the transmitted pulses |
| B. | The interval between transmitted pulses |
| C. | The bandwidth of the receiver IF stages |
| D. | The duty cycle |
| Answer» C. The bandwidth of the receiver IF stages | |
| 54. |
Calculate the effective earth’s radius if the surface refractivity is 301.? |
| A. | 8493 km |
| B. | 8493 mmi |
| C. | 6370 km |
| D. | 6370 mi |
| Answer» B. 8493 mmi | |
| 55. |
In microwave transmission using digital radio, what causes most intersymbol interference?? |
| A. | Delayed spreading |
| B. | Rayleigh fading |
| C. | Random Doppler shift |
| D. | Slow fading |
| Answer» B. Rayleigh fading | |
| 56. |
Oscillators of a klystron tube are maintained? |
| A. | By bunches of electrons passing the cavity grids |
| B. | By plate-to-cathode feedback |
| C. | By feedback between the accelerating grid and the repeller |
| D. | By circulating bunches of electrons within the cavities. |
| Answer» B. By plate-to-cathode feedback | |
| 57. |
Rainfall is an important factor for fading of radio waves at frequencies above? |
| A. | 10 GHz |
| B. | 100 GHz |
| C. | 1 GHz |
| D. | 100 MHz |
| Answer» B. 100 GHz | |
| 58. |
Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction?? |
| A. | Isolator |
| B. | Wave trap |
| C. | Tunnel diode |
| D. | Circulator |
| Answer» B. Wave trap | |
| 59. |
Microwave frequencies are normally regarded as those in the range of? |
| A. | 1 to 500 MHz |
| B. | 1000 to 10,000 GHz |
| C. | 1 to 100 GHz |
| D. | 10 to 1000 GHz |
| Answer» D. 10 to 1000 GHz | |
| 60. |
When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have? |
| A. | A long time constant |
| B. | Low-pass filters |
| C. | The shortest possible time |
| D. | The restricted high-frequency response |
| Answer» D. The restricted high-frequency response | |
| 61. |
A magnetron is operated at a duty cycle of 0.001. It has a peak power output of 100 kilo-watts. Its average power is |
| A. | 10,000 watts |
| B. | 100 watts |
| C. | 1,000 watts |
| D. | 1,000,000 watts |
| Answer» C. 1,000 watts | |
| 62. |
Which of the following operating frequencies is used for the modern loran navigational system? |
| A. | Loran C: 100 kHz |
| B. | Loran D: 10.2 kHz |
| C. | Loran A: 1950 kHz |
| D. | Loran B: 900 kHz |
| Answer» B. Loran D: 10.2 kHz | |
| 63. |
A traveling-wave tube (TWT) amplifies by virtue of |
| A. | The absorption of energy by the signal from an electron stream |
| B. | The effect of an external magnetic field |
| C. | The energy contained the cavity resonators |
| D. | The energy liberated form the collector |
| Answer» B. The effect of an external magnetic field | |
| 64. |
The resonant frequency of a cavity resonator depends upon |
| A. | The mode of operation |
| B. | Its electrical dimensions |
| C. | Its physical dimensions |
| D. | The capacitor which tunes it |
| Answer» D. The capacitor which tunes it | |
| 65. |
If the instantaneous RF potentials on the two sides of a magnetron cavity are of opposite polarity, the operation is in the |
| A. | π mode |
| B. | π/2 mode |
| C. | 2π mode |
| D. | π/4 mode |
| Answer» B. ≈ì√Ñ/2 mode | |
| 66. |
A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor.$ |
| A. | Fathometer |
| B. | Echosounder |
| C. | LORAN |
| D. | SONAR |
| Answer» E. | |
| 67. |
Klystron oscillators are most often used in the frequency range of |
| A. | 300 to 3000 MHz |
| B. | 3000 to 30000 MHz |
| C. | 30 to 30000 MHz |
| D. | 10 to 10000 MHz |
| Answer» C. 30 to 30000 MHz | |
| 68. |
What do you call an attenuation that occurs over many different wavelengths of the carrier? |
| A. | Rayleigh fading |
| B. | Rician fading |
| C. | Wavelength fading |
| D. | Slow fading |
| Answer» E. | |
| 69. |
Coupling into and out of a traveling-wave tube can be accompanied by a |
| A. | Waveguide match |
| B. | Cavity match |
| C. | Direct coax-helix match |
| D. | All of the above |
| Answer» E. | |