# MCQ in Transmission Fundamentals Part 8 | ECE Board Exam

(Last Updated On: May 6, 2020) This is the Multiples Choice Questions Part 8 of the Series in Transmission Fundamentals as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

#### MCQ Topic Outline included in ECE Board Exam Syllabi

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

#### Continue Practice Exam Test Questions Part 8 of the Series

351. A coaxial cable with two layers of foil insulation and two layers of braided shielding.

B. Double shielding

C. Triple shielding

D. Shielding

Solution:

352. A type of coaxial cable that has a tubular outer conductor surrounds the center conductor coaxially and the insulating material is air.

A. Gas-filled coaxial cable

B. Rigid air coaxial cable

C. Solid coaxial cable

D. Flexible cable

Solution:

353. If the length of an open-circuited stub is less than quarter-wavelength but greater than 0, the stub behaves as

A. Inductor

B. Capacitor

C. Resistor

D. Complex

Solution:

354. Type of coaxial cable where the outer conductor is braided, flexible, and coaxial to the center conductor.

A. Gas-filled coaxial cable

B. Rigid air coaxial cable

C. Solid flexible coaxial cable

D. Flexible cable

Solution:

355. A 50-ohm coax is connected to a 73-ohm antenna. The SWR is

A. 0.685

B. 1

C. 1.46

D. 2.92

Solution:

356. Defined as the impedance seen looking at an infinitely long line or the impedance seen looking into a finite length of the line that is terminated in a purely resistive load with the resistance equal to the characteristic impedance of the line.

A. Input impedance

B. Surge impedance

C. Output impedance

D. Circuit impedance

Solution:

357. Determine the characteristic impedance for an air dielectric two-wire parallel transmission line with a D/r ratio of 12.22

A. 150 ohms

B. 120 ohms

C. 75 ohms

D. 300 ohms

Solution:

358. Determine the characteristic impedance for an RG-59A coaxial cable with the following specifications: d = 0.025 inches, D = 0.15 inches, and dielectric constant of 2.23

A. 120 ohms

B. 72 ohms

C. 150 ohms

D. 75 ohms

Solution:

359. Determine the characteristic impedance for an RG-59A coaxial cable with the following specifications: L=0.118 uH/ft and C = 21 pF/ft

A. 150 ohms

B. 72 ohms

C. 75 ohms

D. 100 ohms

Solution:

360. It is used to express the attenuation or signal loss and the phase shift per unit length of the transmission line.

A. Propagation coefficient

B. Propagation constant

C. Propagation factor

D. Any of these

Solution:

361. For matched condition, what is the relationship of load and characteristic impedance?

A. Greater than

B. Less than

C. Equal

D. Impossible to say

Solution:

362. It is defined simply as the ratio of the actual velocity of propagation of an electromagnetic wave through a given medium to the velocity of propagation through a vacuum or free space.

A. Velocity factor

B. Velocity propagation

C. Index of refraction

D. Phase delay

Solution:

363. It is simply the permittivity of the material

A. Permittivity

B. Insulation constant

C. Dielectric constant

D. Resistivity

Solution:

364. For a given length of RG 8A/U coaxial cable with distributed capacitance of 96.6 pF/m, a distributed inductance of 241.56 nH/m, and a relative dielectric constant of 2.3, determine the velocity of propagation.

A. 1.07 x 10^8 m/s

B. 2.3 x 10^7 m/s

C. 3.28 x 10^8 m/s

D. 2.07 x 10^8 m/s

Solution:

365. For a given length of RG 8A/U coaxial cable with distributed capacitance of 96.6 pF/m, a distributed inductance of 241.56 nH/m, and a relative dielectric constant of 2.3, determine the velocity factor

A. 1.2

B. 0.66

C. 0.7

D. 0.5

Solution:

366. If the length of an open-circuited stub is greater than quarter-wavelength but less than half-wavelength, the stub behaves as

A. Inductor

B. Capacitor

C. Resistor

D. Complex

Solution:

367. Delay line is a function of what two parameters?

A. Resistance and capacitance

B. Resistance and susceptance

C. Inductance and resistance

D. Inductance and capacitance

Solution:

368. How is the time delay calculated in a coaxial cables with a dielectric constant of 0.66?

A. 0.56 sec

B. 0.67 sec

C. 0.45 sec

D. 1.2 sec

Solution:

369. Three feet is one wavelength at a frequency of

A. 100 MHz

B. 164 MHz

C. 300 MHz

D. 328 MHz

Solution:

370. When current flows through a conductor, the loss introduced as a function of resistance and current is called _______.

A. Inductance loss

B. Conductor loss

C. Voltage loss

D. Skin effect

Solution:

371. For maximum absorption of power at the antenna, the relationship between the characteristic impedance of the line Zo and the load impedance ZL should be

A. Zo = ZL

B. Zo > ZL

Solution:

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372. The ratio of the AC resistance and the DC resistance.

A. Impedance ratio

B. Susceptance ratio

C. Resistance ratio

D. Conductance ratio

Solution:

373. The difference in potential between two conductors of a metallic transmission line causes ______.

A. Conductor loss

B. Dielectric heating

D. Corona

Solution:

374. If the length of a short-circuited stub is greater than quarter-wavelength but less than half-wavelength, the stub behaves as

A. Inductor

B. Capacitor

C. Resistor

D. Complex

Solution:

375. If the separation between the conductors in a metallic transmission line is an appreciable fraction of a wavelength, the electrostatic and electromagnetic fields that surround the conductor cause the line to act as if it were an antenna and transfer energy to any nearby material. This energy radiated is called ______.

B. Power loss

C. Coupling loss

D. Corona

Solution:

376. The minimum voltage along a transmission line is 260 V, while the maximum is 390 V. The SWR is

A. 0.67

B. 1.0

C. 1.2

D. 1.5

Solution:

377. It occurs whenever a connection is made to or from a transmission line or when two sections of transmission line are connected together.

A. Power loss

B. Coupling loss

D. Resistance loss

Solution:

378. Which of the following is not a common transmission line impedance?

A. 50 ohms

B. 75 ohms

C. 120 ohms

D. 300 ohms

Solution:

379. It is a luminous discharge that occurs between the two conductors of a transmission line when the difference in potential between them exceeds the breakdown voltage of a dielectric insulator.

A. Resistance loss

B. Corona

D. Power loss

Solution:

380. Voltage that propagates down the load.

A. Reflected voltage

B. Standing wave ratio

C. Incident voltage

D. Reflection voltage

Solution:

381. Voltage that propagates from the load towards the source.

A. Reflected voltage

B. Standing wave ratio

C. Reflection coefficient

D. Incident voltage

Solution:

382. A transmission line with no reflected power.

A. Flat

B. Resistive

C. Non resonant line

D. Any of these

Solution:

383. It is a vector quantity that represents the ratio of reflected voltage to incident voltage or the reflected current and the incident current

A. Reflection coefficient

C. Standing wave ratio

D. Traveling waves

Solution:

384. With a mismatched line, two electromagnetic waves traveling in opposite direction, present on the line on the same time.

A. Standing wave ratio

B. Reflection coefficient

C. Standing waves

D. Traveling waves

Solution:

385. The two traveling waves sets up an interference pattern called _______.

A. Standing wave ratio

B. Reflection coefficient

C. Standing waves

D. Traveling waves

Solution:

386. It is defined as the ratio of the maximum voltage to the minimum voltage or the maximum current to the minimum current of a standing wave in a transmission line.

A. Standing wave ratio

B. Normalized impedance

C. Reflection coefficient

D. Any of these

Solution:

387. For a transmission line with an incident voltage of 5 V and a reflected voltage of 3 V, determine the reflection coefficient.

A. 0.4

B. 0.6

C. 0.5

D. 0.7

Solution:

388. A ratio expressing the percentage of incident voltage reflected on a transmission line is known as the

A. Velocity factor

B. Standing wave ratio

C. Reflection coefficient

D. Line efficiency

Solution:

389. There is an impedance inversion in every ______.

A. Half wavelength

B. Quarter wavelength

C. Full wavelength

D. Three-eights of a wavelength

Solution:

390. The characteristic impedance of a transmission line does not depend upon its

A. Length

B. Conductor diameter

C. Conductor spacing

D. None of these

Solution:

391. ______ are used to match transmission lines to purely resistive loads whose resistance is not equal to the characteristic impedance of the line.

A. Stub

B. Slotted lines

C. Quarter-wavelength transformer

D. Short circuited lines

Solution:

392. To match a transmission line with a reactive load _______.

A. Use stub matching

B. Use a slotted line

C. Used a Q-section

D. Use an open circuited lines

Solution:

393. A technique that can be used to locate an impairment in metallic cable.

A. TDR

B. Wattmeter

C. Voltmeter

D. SWR meter

Solution:

394. A pulse is transmitted down a cable that has a velocity of propagation of 0.8c. The reflected signal is received 1us later. How far down the cable is the impairment?

A. 240 m

B. 15 m

C. 60 m

D. 120 m

Solution:

395. Using TDR, a transmission line impairment is located 3000 m from the source. For a velocity propagation of 0.9c, determine the time elapsed from the beginning of the pulse to the reception of the echo

A. 11.11 µs

B. 10.12 µs

C. 22.22 µs

D. 21.14 µs

Solution:

396. A flat conductor separated from a ground plane by an insulating dielectric material.

A. Stripline

B. Waveguide

C. Microstrip

D. Coaxial cable

Solution:

397. A flat conductor sandwich between two ground planes.

A. Stripline

B. Waveguide

C. Microstrip

D. Coaxial cable

Solution:

398. Indicate the false statement. The SWR on a transmission line is infinity; the line is terminated in

A. A short circuit

B. A complex impedance

C. An open circuit

D. A pure reactance

Solution:

399. The most commonly used transmission line is a

A. Two-wire balance line

B. Singe wire

C. Three-wire line

D. Coax

Solution:

400. A short-circuited half-wavelength line acts like a

A. Parallel resonant circuit

B. Series resonant circuit

C. Oscillator

D. LC circuit

Solution:

#### Questions and Answers in Transmission Fundamentals Series

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

MCQ in Transmission Fundamentals
PART 1: MCQ from Number 1 – 50                        Answer key: PART 1
PART 2: MCQ from Number 51 – 100                   Answer key: PART 2
PART 3: MCQ from Number 101 – 150                 Answer key: PART 3
PART 4: MCQ from Number 151 – 200                 Answer key: PART 4
PART 5: MCQ from Number 201 – 250                 Answer key: PART 5
PART 6: MCQ from Number 251 – 300                 Answer key: PART 6
PART 7: MCQ from Number 301 – 350                 Answer key: PART 7
PART 8: MCQ from Number 351 – 400                 Answer key: PART 8
PART 9: MCQ from Number 401 – 450                 Answer key: PART 9
PART 10: MCQ from Number 451 – 500                Answer key: PART 10

### Complete List of MCQ in Communications Engineering per topic

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