### Online Questions and Answers Topic Outline

- MCQs in Transmission System
- MCQs in Transmission Medium
- MCQs in Velocity and Line Wavelength
- MCQs in Characteristics Impedance
- MCQs in Primary Line Constants and Propagation Constants
- MCQs in Standing Waves
- MCQs in Voltage Standing Wave Ratio
- MCQs in Telephone Lines and Cables
- MCQs in Wave Guides
- MCQs in Balanced and Unbalanced Lines
- MCQs in Twisted pair wire, Coaxial Cable
- MCQs in Decibel
- MCQs in Signal and Noise Fundamentals

### MCQs in Transmission Fundamentals Series

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

**Transmission Fundamentals 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 Questions Part V of the Series

201. If the 10% of the microwave power is reflected at the mismatch, find the return loss.

- a. 0.1 dB
- b. 10 dBm
- c. -10 dB
- d. -10 dBm

202. If the return loss is 20 dB, find the present reflected power.

- a. 1%
- b. 10%
- c. 5%
- d. 20%

203. Convert “ten times bigger” to the equivalent numerical dB

- a. 20 dB
- b. 15 dB
- c. 5 dB
- d. 10 dB

204. Convert “one-half as large” to equivalent numerical dB

- a. 3 dB
- b. -3 dB
- c. 2 dB
- d. -2 dB

205. Special semiconductor diode use for electronically adjustable attenuation

- a. Ideal diode
- b. PIN diode
- c. Zener diode
- d. Tunel diode

206. A 50 ohm line is probed and found to have a SWR of 2.6, what are the two possible quarter wave transformers sizes that may be used to match the load to the line of the transformer are properly positioned.

- a. 22 ohm, 82 ohm
- b. 31 ohm, 80.5 ohm
- c. 26.2 ohm, 12.71 ohm
- d. 12.32 ohm, 26.7 ohm

207. A balanced load of 900 ohm pure resistance is fed through a balanced 600 ohm transmission line which is 90 electrical degree long. The balanced 600 ohm transmission line is in turn fed from a 50 ohm coaxial line by means of a half-wave balancing section. What is the standing wave ratio on the 600 ohm line?

- a. 1.0
- b. 2.5
- c. 1.5
- d. 2.0

208. Given cascaded circuit; first stage is a filter circuit with insertion loss of 3 dB, followed by an amplifier with a gain of 10 dB and followed by cable having an insertion loss of 1 dB. If the input power of the filter circuit is 1 mW, find the total insertion loss.

- a. 6 dBm
- b. 5 dBm
- c. 7 dBm
- d. 2 dBm

209. For a short circuited line or open circuited line, the standing wave ratio value is always _____.

- a. Unity
- b. Infinity
- c. Zero
- d. Cannot be determined

210. If the voltage reading at a particular section of a transmission line is maximum, the current reading should be:

- a. Maximum
- b. Minimum
- c. Average
- d. Zero

211. If five signals entered to an X-device at 3 dBm each, find the output power in dBm.

- a. 12 dBm
- b. 11 dBm
- c. 10 dBm
- d. 8 dBm

212. Given incident power of 0.4 mW and insertion loss of 3 dB, find the transmitted power.

- a. 0.2 mW
- b. 0.3 mW
- c. 0.4 mW
- d. 0.5 mW

213. The reflected voltage and reflected current along the transmission line are always:

- a. 180
^{o}out of phase - b. In phase
- c. Same value
- d. 90
^{o}in phase

214. If the direction of the reflection coefficient is 90^{o}, the nature of the lien is,

- a. Resistive
- b. Purely inductive
- c. Purely capacitive
- d. None of these

215. What are the three types of microwave transmission line?

- a. Coaxial cable, open wire line, waveguide
- b. Coaxial cable, stripline, waveguide
- c. Open-wire line, waveguide, coaxial line
- d. None of these

216. If the incident power is -27 dBm and insertion loss of 20 dB, find for the transmitted power.

- a. 12 dBm
- b. 7 dBm
- c. 2 dBm
- d. 0 dBm

217. Energy applied to a transmission line may become dissipated before reaching the load.

- a. Radiation
- b. Conductor heating
- c. Dielectric heating
- d. All of the above

218. The velocity of light is very nearly 3 x 10^{8} m/s in a vacuum and ___ in all other media.

- a. Higher
- b. Slower
- c. Same
- d. All of these

219. At a point exactly a quarter-wavelength from the load, the current is ______.

- a. 180 degrees in of phase
- b. 180 degrees out of phase
- c. Permanently zero
- d. None of these

220. Is a piece of transmission line which is normally short-circuited at the far end.

- a. Terminator
- b. Stub
- c. Quarter wave transformer
- d. None of these

221. For high frequencies, the best dielectric may be_______.

- a. Polyethylene
- b. Polyethylene foam
- c. Teflon
- d. None of these

222. Characteristic impedance are sometimes called _______.

- a. Ohmic resistance
- b. Surge impedance
- c. Wave impedance
- d. None of these

223. A transmission line is connected to a mismatched load. Calculate the VSWR in dB if the reflection coefficient is 0.25

- a. 2.6 dB
- b. 1.67 dB
- c. 4.3 dB
- d. 3.6 dB

224. Is a power tool for the RF design

- a. Calculator
- b. Graphical solution
- c. Smith chart
- d. None of these

225. When will the system encounter a tremendous increase of interference.

- a. When return loss is 0 dB
- b. When the incident power is higher than the reflected
- c. When the transmission line used is coaxial cable
- d. None of these

226. In a two-stage amplifier, amplifier 1 has a noise figure of 3 dB and a gain of 20 dB. The second amplifier has a noise figure of 6 dB. Find the total noise figure.

- a. 3.1 dB
- b. 4.2 dB
- c. 2.6 dB
- d. 2.27 dB

227. If the return loss is 13 dB, find the equivalent SWR.

- a. 1.6
- b. 3.2
- c. 1.56
- d. 2.6

228. Which of the following will you choose in order to minimize mismatch?

- a. SWR = 1.4
- b. T1 = 0.81
- c. Return loss = 20 dB
- d. None of these

229. If the equipment has input power of 33 dBm, what is the gain of the resulting output power is 10 dBm.

- a. -26 dBm
- b. -23 dBm
- c. -33 dBm
- d. 33 dBm

230. A stripline transmission line is built on a 4 mm thick printed wiring board that has a relative dielectric constant of 5.5. Calculate the characteristics impedance of the width of the strip is 2 mm.

- a. 256 ohms
- b. 321 ohms
- c. 126 ohms
- d. 425.35 ohms

231. A 50 ohms transmission line is connected to a 30 ohm resistive load. Calculate reflection coefficient.

- a. 0.35
- b. 0.25
- c. 0.10
- d. 0.15

232. The term _________ implies a sine wave of constant amplitude, phase and frequency.

- a. Steady state
- b. State of constant
- c. State of calamity
- d. Constant sine wave

233. Is defined as the ratio of the reflected signal to the incident signal.

- a. VSWR
- b. SWR
- c. Reflection coefficient
- d. None of these

234. It is a measure of one way loss of power in a transmission line due to reflection from the load.

- a. Return loss
- b. Transmission loss
- c. Propagation loss
- d. None of these

235. If the velocity factor is equal to 0.66, the speed of light will be_____.

- a. Increase
- b. Decrease
- c. Same
- d. None of these

236. In 1939, _________ published a graphical device for solving transmission line design.

- a. Phillip A. Smith
- b. Phillip R. Smith
- c. Phillip H. Smith
- d. Phillip S. Smith

237. In order to make the smith chart universal, the impedances along the pure resistance line are _________.

- a. Normal
- b. Normalized
- c. Open circuit
- d. Short circuit

238. Calculate the gain off an amplifier with an input power 10 kW and an output power of 200 kW.

- a. 15 dB
- b. 13 dB
- c. 20 dB
- d. 10 dB

239. A perfect termination for a transmission line.

- a. Receiving end
- b. Load
- c. Antenna
- d. Terminal end

240. It can be measured, and includes losses due to reflection and absorption inside the component

- a. Fading
- b. Attenuation
- c. Insertion loss
- d. Return loss

241. A component that samples the microwave signal traveling in one direction down a transmission line

- a. Isolator
- b. Directional coupler
- c. Combiner
- d. attenuator

242. A transmission line having air dielectric is operated at a frequency of 110 MHz. What is the phase shift constant of the line is degrees per inch?

- a. 2.56
- b. 3.35
- c. 4.6
- d. 1.25

243. Consider the three networks in series, the first is an attenuator with a 12 dB loss, the second network is an amplifier with 35 dB gain, and the third has an insertion loss of 10 dB. The input of the first network is 4 mW; what is the output of the third network in watts?

- a. 0.798 W
- b. 0.00798 W
- c. 0.0798 W
- d. 798 W

244. Is a power level related to 1 mW.

- a. dB
- b. dBm
- c. dBM
- d. dBW

245. A transmission unit used in a number of Northern European countries as an alternative to the decibel is ________.

- a. Attenuation
- b. Loss
- c. Neper
- d. dB loss

246. Adding two +30 dBm will produce how much dBm at the output.

- a. 60 dBm
- b. 15 dBm
- c. 23 dBm
- d. 33 dBm

247. Determines how the voltage or current decreases with distance

- a. Phase-shift coefficient
- b. Attenuation coefficient
- c. Propagation coefficient
- d. Numerical coefficient

248. Determines the phase angle of the voltage or current variation with distance

- a. Phase-shift coefficient
- b. Attenuation coefficient
- c. Propagation coefficient
- d. Numerical coefficient

249. Determines variation of voltage or current with distance along transmission line

- a. Phase-shift coefficient
- b. Attenuation coefficient
- c. Propagation coefficient
- d. Numerical coefficient

250. The R, L, G, and C in the transmission line are called________.

- a. Passive elements
- b. Active elements
- c. Line primary constant
- d. Reactances

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