### Online Questions and Answers Topic Outline

- MCQs in Basic considerations
- MCQs in Wire Radiators in Space
- MCQs in Isotropic Radiator
- MCQs in Current and Voltage Distributions
- MCQs in Resonant and Non-resonant Antennas
- MCQs in Antenna Terms and Definition
- MCQs in Antenna Gain and Resistance
- MCQs in Bandwidth, Beamwidth and Polarization
- MCQs in Grounded and Ungrounded Antennas
- MCQs in Grounding Systems and Matching Systems
- MCQs in Antenna Types
- MCQs in Directional and Non-directional Antennas
- MCQs in Microwave Antennas
- MCQs in Wideband and Special Purpose Antennas

### MCQs in Antennas Series

Following is the list of multiple choice questions in this brand new series:

**Antennas MCQs**

**MCQs from Number 1 – 50**Answer key:

**PART I**

**MCQs from Number 51 – 100**Answer key:

**PART II**

**MCQs from Number 101 – 150**Answer key:

**PART III**

**MCQs from Number 151 – 200**Answer key:

**PART IV**

**MCQs from Number 201 – 250**Answer key:

**PART V**

**MCQs from Number 251 – 300**Answer key:

**PART VI**

**MCQs from Number 301 – 350**Answer key:

**PART VII**

**MCQs from Number 351 – 400**Answer key:

**PART VIII**

**MCQs from Number 401 – 450**Answer key:

**PART IX**

**MCQs from Number 451 – 500**Answer key:

**PART X**

### Continue Practice Exam Test Question Part VI of the Series

251. It is a metallic conductor system capable of radiating and capturing electromagnetic energy

- a. transmission lines
- b. antenna
- c. waveguides
- d. load

252. A directional antenna with two or more elements is known as

- a. folded dipole
- b. ground plane
- c. loop
- d. array

253. The ratio of the focal length to the diameter of the mouth of the parabola is called _____.

- a. aperture
- b. focal point
- c. foci
- d. major axis

254. The impedance of a dipole is about

- a. 50-ohm
- b. 73-ohm
- c. 93-ohm
- d. 300-ohm

255. A special type of transmission line that consist of conducting metallic tube through which high frequency electromagnetic energy is propagated

- a. medium
- b. microstrip
- c. stripline
- d. waveguide

256. Calculate the angle of declination for an antenna using a polar mount at a latitude of 45 degrees

- a. 3.2 degrees
- b. 1.3 degrees
- c. 4.2 degrees
- d. 6.81 degrees

257. The cone angle of the flare angle of a conical horn antenna is approximately

- a. 55 degrees
- b. 45 degrees
- c. 40 degrees
- d. 50 degrees

258. Electrical energy that has escaped into free space in the form of transverse electromagnetic waves

- a. Radio waves
- b. Frequency
- c. Signal
- d. Wavelength

259. The length of the ground plane vertical at 146 MHz is

- a. 1.6 ft
- b. 1.68 ft
- c. 2.05 ft
- d. 3.37 ft

260. Using a small reflector to beam waves to the larger parabolic reflector is known as

- a. Focal feed
- b. Horn feed
- c. Cassegrain feed
- d. Coax feed

261. The plane parallel to the mutually perpendicular line in the electric and magnetic fields is called _______.

- a. wavefront
- b. point source
- c. isotropic source
- d. rays

262. What is the beamwidth of a parabolic antenna with a diameter of 5 meters and an operating frequency of 10 GHz?

- a. 0.5 degrees
- b. 0.675 degrees
- c. 0.348 degrees
- d. 3.48 degrees

263. The horizontal radiation pattern of a dipole is a

- a. circle
- b. figure of eight
- c. clover leaf
- d. narrow beam

264. The size of antenna is inversely proportional to _______.

- a. frequency
- b. power
- c. radiation resistance
- d. wavelength

265. A popular half – wave antenna is the

- a. Ground plane
- b. End-fire
- c. Collinear
- d. Dipole

266. Calculate the gain of a parabolic antenna using a 2.5-m radius dish operating at 10 GHz.

- a. 166.673 dB
- b. 83.7 dB
- c. 52.2 dB
- d. 45.6 dB

267. It is the ratio of the radiated to the reflected energy

- a. Radiation resistance
- b. Radiation efficiency
- c. Radiation constant
- d. Radiation antenna

268. The feed mechanism in a parabolic antenna that radiates the electromagnetic energy.

- a. Primary antenna
- b. Reflectors
- c. Secondary antenna
- d. Focal point

269. It is a polar diagram or graph representing field strengths or power densities at various angular positions relative to an antenna

- a. Side lobe
- b. Front lobe
- c. Radiation pattern
- d. Radiation constant

270. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna resistance of 8 ohms, a directive gain of 20 and an input power of 100W, determine the antenna gain.

- a. 12.55 dB
- b. 10.43 dB
- c. 11.21 dB
- d. 9.78 dB

271. The radiation pattern plotted in terms of electric field strength or power density

- a. absolute radiation pattern
- b. relative radiation pattern
- c. absolute front lobe pattern
- d. absolute side lobe pattern

272. Calculate the characteristic impedance of a quarter – wavelength section used to connect a 300-ohm antenna to a 75-ohm line

- a. 150 ohms
- b. 120 ohms
- c. 130 ohms
- d. 110 ohms

273. Plots of field strength or power density with respect to the value at a reference point

- a. absolute front lobe pattern
- b. relative front lobe pattern
- c. relative front lobe pattern
- d. relative radiation pattern

274. What must be the height of a vertical radiator one half wavelength high if the operating frequency is 1100 kHz?

- a. 120 m
- b. 136 m
- c. 115 m
- d. 124 m

275. Lobes adjacent to the front lobe

- a. Diagonal lobes
- b. Side lobes
- c. Front lobes
- d. Back lobes

276. Lobes in a direction exactly opposite of the front lobe

- a. Side lobes
- b. Adjacent lobes
- c. Front lobes
- d. Back lobes

277. Calculate the efficiency of an antenna that has a radiation resistance of 73 ohms and an effective dissipation resistance of 5 ohms

- a. 98.3%
- b. 93.6%
- c. 90.7%
- d. 95.5%

278. The line bisecting the major lobe, or pointing from the center of the antenna in the direction of maximum radiation is called _______.

- a. line of shoot
- b. diagonal shoot
- c. bisecting shoot
- d. antenna shoot

279. The ammeter connected at the base of a Marconi antenna has a certain reading. If this reading is increased 2.77 times, what is the increase in output power?

- a. 3.45
- b. 1.89
- c. 2.35
- d. 7.67

280. Refers to a field pattern that is close to the antenna.

- a. Induction field
- b. Far field
- c. Radiation field
- d. Capture field

281. A half-wave dipole is driven with a 5-W signal at 225 MHz. A receiving dipole 100 km. Calculate the received power into a 73-ohm receiver.

- a. 23.5 pW
- b. 7.57 pW
- c. 5.64 pW
- d. 1.26 pW

282. It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates.

- a. Directive gain
- b. Antenna efficiency
- c. Radiation resistance
- d. Antenna resistance

283. What is the effective radiated power of a television broadcast station if the output of the transmitter is 1000W, antenna transmission line loss is 50W, and the antenna power gain is 3?

- a. 1250 W
- b. 2370 W
- c. 2130 W
- d. 2850 W

284. It is the ratio of the power radiated by an antenna to the sum of the power radiated and the power dissipated.

- a. radiation resistance
- b. coupling coefficient
- c. antenna efficiency
- d. antenna beamwidth

285. It is the ratio of the power radiated by the antenna to the total input power.

- a. antenna efficiency
- b. reflection coefficient
- c. standing wave ratio
- d. radiation resistance

286. If a 500 kHz transmitter of a constant power produces field strength of 100 uV/m at a distance of 100 mi from the transmitter, what would be the theoretical field strength at a distance of 200 mi from the transmitter?

- a. 45 uV/m
- b. 100 uV/m
- c. 50 uV/m
- d. 35 uV/m

287. An antenna that transmits or receives equally well in all directions is said to be _____.

- a. omnidirectional
- b. bidirectional
- c. unidirectional
- d. quasidirectional

288. It is the ratio of the power density radiated in a particular direction to the power density radiated to the same point by a reference antenna, assuming both antennas are radiating the same amount of power

- a. power gain
- b. directive gain
- c. total gain
- d. system gain

289. If the field intensity of 25 mV/m develops 2.7 V in a certain antenna, what is its effective height?

- a. 110 m
- b. 100 m
- c. 98 m
- d. 108 m

290. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization ______.

- a. is vertical
- b. is horizontal
- c. is circular
- d. cannot be determined from the information given

291. If the power of a 500 kHz transmitter is increased from 150 W to 300 W, what would be the percentage change in field intensity at a given distance from the transmitter?

- a. 141%
- b. 150%
- c. 100%
- d. 133%

292. It is the same with directive gain except that the total power fed to the antenna is used and the antenna efficiency is taken into account.

- a. system gain
- b. power gain
- c. directive gain
- d. total gain

293. A hip-radio telephone transmitter operates on 2738 kHz. At a certain point distant from the transmitter, the 2738 kHz signal is measured field of 147 mV/m. The second harmonic field at the same point is measured as 405 uV/m. To the nearest whole unit in decibels, how much has the harmonic emission been attenuated below the 2738 kHz fundamental?

- a. 43.2 dB
- b. 51.2 dB
- c. 35.1 dB
- d. 25.1 dB

294. It is the equivalent power that an isotropic antenna would have to radiate to achieve the same power density in the chosen direction at a given point as another antenna.

- a. EIRP
- b. ERP
- c. IRL
- d. RSL

295. When the energy is applied to the antenna at a point of high – circulating current.

- a. voltage-fed antenna
- b. power-fed antenna
- c. current-fed antenna
- d. impedance-fed antenna

296. For a transmit antenna with a power gain of 10 and an input power of 100 W, determine the EIRP in watts.

- a. 30 dBW
- b. 40 dBW
- c. 50 dBW
- d. 20 dBW

297. If energy is applied at the geometrical center of antenna, the antenna is said to be _____.

- a. center-fed
- b. end-fed
- c. quarterwave-fed
- d. halfwave-fed

298. For a transmit antenna with a power gain of 10 and an input power of 100 W, determine the power density at a point 10 km from the transmit antenna

- a. 0.574 uW/m^2
- b. 0.796 uW/m^2
- c. 1.24 uW/m^2
- d. 0.981 uW/m^2

299. For a transmit antenna with a radiation resistance of 72 ohms, an effective antenna resistance of 8 ohms, a directive gain of 20 and an input power of 100 W, determine the antenna efficiency.

- a. 90%
- b. 96%
- c. 98%
- d. 96%

300. The fields surrounding the antenna do not collapse their energy back into the antenna but rather radiate it out in space.

- a. induction field
- b. near field
- c. radiation field
- d. magnetic field

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