### 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 X of the Series

451. Considering a coaxial transmission line, maximum voltage on the line divided by the minimum voltage equals the

- a. Characteristic impedance
- b. ISWR
- c. VSWR
- d. Inductive reactance

452. In a transmission line, if the SWR or maximum current to a minimum current ratio of 2:1, the ratio of the maximum voltage to the minimum voltage is

- a. 1:4
- b. 4:1
- c. 1:2
- d. 2:1

453. Transmission lines are either balanced or unbalanced with respect to

- a. Negative terminal
- b. Input
- c. Ground
- d. Positive terminal

454. The load is properly matched with the transmission line if the standing wave ratio is equal to

- a. 50
- b. 10
- c. 5
- d. 1

455. The radiation resistance of a quarterwave antenna is

- a. 49 ohms
- b. 288 ohms
- c. 72 ohms
- d. 144 ohms

456. A radio transmission line of 500 ohms impedance is to be connected to an antenna having an impedance of 200 ohms. What is the impedance of a quarter wave matching line?

- a. 300
- b. 316
- c. 316.5
- d. 361

457. The VSWR for a line terminated in its Zo is

- a. 0
- b. 1
- c. 1.5
- d. Infinity

458. Which of the following is used to measure SWR?

- a. Multimeter
- b. Reflectometer
- c. Spectrum analyzer
- d. Oscilloscope

459. A 75 – j50 ohm load is connected to a coaxial transmission line of Zo = 75 ohms at 10 GHz. The best method of matching consists in connecting

- a. A short circuited stub at the load
- b. A capacitance at some specific distance from the load
- c. An inductance at the load
- d. A short-circuited stub at some specific distance from the load

460. For a two-wire line, Zo is higher when

- a. The wire size is small with respect to the spacing of the conductors
- b. The spacing is varied in accordance with the frequency
- c. The D:d ratio is smaller
- d. The wire is large with respect to the spacing of the conductors

461. A resultant wave due to the combination of incident and reflected wave

- a. Electromagnetic wave
- b. Sine wave
- c. Standing wave
- d. Current

462. For transmission line load matching over a range of frequencies, it is best to use a

- a. Balun
- b. Broadband directional coupler
- c. Double stub
- d. Single stub

463. If the load impedance matches the characteristic impedance of the line, there are _____ standing waves.

- a. More
- b. Less
- c. No
- d. Ten(10)

464. VSWR stands for

- a. Voltage sending wave ratio
- b. Voltage receiving wave ratio
- c. Very small wave radiation
- d. Voltage standing wave ratio

465. Reflections on a transmission line can occur when

- a. Impedance of the source and load are matched
- b. Impedance of the source and the load are mismatched
- c. Resonance conditions are obtained
- d. Power transfer between source and load is maximum

466. A transmission line with characteristic impedance (Zo) of 300 ohms is terminated in a resistance load (RI). If by measurement, the minimum and maximum voltage through the load are 12 and 20 micro volts, respectively, what is the SWR?

- a. 1.67
- b. 0.6
- c. 6.7
- d. 3.67

467. A measure of the mismatched between line and load impedance is called as

- a. Reflection coefficient
- b. Standing wave ratio
- c. Loss
- d. Standing waves

468. Transmission lines when connected to antenna have

- a. Capacitive load
- b. Resistive load whose resistance is less than characteristic impedance
- c. Resistive load at the resonant frequency
- d. Resistive load whose resistance is greater than the characteristic impedance of the line

469. At matched condition, SWR is equal to

- a. Zero
- b. One
- c. 100
- d. Infinite

470. An HF transmission line has a characteristic impedance of 600 ohms and is terminated by an antenna. The SWR along the line when the antenna impedance is 500 ohms is

- a. 1.2:1
- b. 1:2.1
- c. 2:1
- d. 1:2

471. A characteristic of an infinite transmission line is that

- a. The impedance in equals impedance out
- b. It carries waves at the velocity of light
- c. It can be connected to mismatched loads
- d. The impedance varies with the length of the line

472. A quarter wave transmission line shorted at the end:

- a. Has the characteristics of parallel tuned circuit
- b. Has the characteristics of a series tuned circuit
- c. Has a minimum current at the end
- d. Reflects a low impedance to the supply

473. The outer conductor of a coaxial transmission line is usually grounded at the:

- a. Input and output
- b. Output only
- c. Input only
- d. Point of infinite resistance

474. A certain feedline has a high SWR. It can be caused by:

- a. An impedance mismatched
- b. Use of non-resonant line
- c. Matching the load to the line
- d. Excessive transmitter output

475. If the input impedance of an antenna is 300 ohms and it is fed with a 600 ohm balanced transmission line, the SWR on the line is

- a. 4
- b. 3
- c. 2
- d. 0.5

476. A radio transmission line of 300 ohms impedance to be connected to an antenna having an input impedance of 150 ohms. The impedance if a quarter wave matching line is ___ ohms

- a. 212
- b. 450
- c. 600
- d. 150

477. The ratio of the reflected voltage to the incident voltage on the transmission line is termed as

- a. Reflection coefficient
- b. Standing wave ratio
- c. Loss
- d. Standing waves

478. Indicate the three types of transmission line energy losses

- a. Radiation, I
^{2}R and dielectric Heating - b. Conductor heating, dielectric heating and radiation resistance
- c. I
^{2}R, RL and temperature - d. Dielectric separation insulation breakdown and radiation

479. Termination means

- a. Load connected to the output end of a transmission line
- b. Result of disconnecting a line from a transmitter
- c. Looking back impedance of a line with no load
- d. Result of cutting both ends of a conductor

480. When transmission line uses ground return, it is called a/n _____ line.

- a. Ungrounded
- b. Unbalanced
- c. Grounded
- d. Balanced

481. Permeability is the measure of superiority of a material over a vacuum as a path of magnetic lines of force. The permeability of free space is equal to _____ henry/meter

- a. 1.257 x 10
^{-6} - b. 1.527 x 10
^{-6} - c. 7.251 x 10
^{-6} - d. 5.217x10
^{-6}

482. The most commonly used transmission line is a

- a. Two-wire balanced line
- b. Single line
- c. Three-wire line
- d. Coax

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

- a. Length
- b. Conductor diameter
- c. Conductor spacing
- d. Thickness of armor

484. What is the impedance of a balance 4-wire with a diameter of 0.25cm and spaced 2.5 cm apart using an insulator with a dielectric constant of 2.56?

- a. 100 ohms
- b. 65 ohms
- c. 75 ohms
- d. 50 ohms

485. It is required to match a 73-ohm antenna to a 600 ohm polyethylene coaxial feeder line, with a velocity factor of 0.66 by means of a quarter wave matching a transformer. At a frequency of 150 MHz, the impedance of the matching section is____ ohms.

- a. 209.28
- b. 310.5
- c. 150.28
- d. 450.82

486. If the terminating impedance is exactly equal to the characteristic impedance of the transmission line, the return loss is____

- a. Zero
- b. Infinity
- c. One
- d. Negative

487. The characteristic impedance of a transmission line is the impedance measured at the ____ when its length is infinite.

- a. Shorted end of the line
- b. Midsection
- c. Input
- d. Output

488. The characteristic impedance of a transmission line is 70 ohms and has a load of 35 ohms. The SWR and reflection coefficient are _____ and _____ respectively

- a. 2 and 0.333
- b. 1 and 0.666
- c. 2 and 0.666
- d. 1 and 0.333

489. It is required to match a 200 ohm load to a 300 ohm transmission line to reduce the SWR and attain resonance. A quarter wave transformer used, directly connected to the load has a Zo of ____ ohms.

- a. 245
- b. 425
- c. 524
- d. 254

490. What quarter wave transformer will match a 100 ohm-line to an antenna whose value is 175 ohms?

- a. 150 ohms
- b. 137.5 ohms
- c. 132.29 ohms
- d. 16.58 ohms

491. The mismatch between antenna and transmission line impedance cannot be corrected by

- a. Using an LC network
- b. Adjusting antenna length
- c. Using a balun
- d. Adjusting the length of the transmission line

492. A pattern of voltage and current variation along a transmission line not terminated in its characteristic impedance is called

- a. An electric field
- b. Radio waves
- c. Standing waves
- d. Magnetic field

493. The most desirable value of SWR on a transmission line is

- a. 0
- b. 1
- c. 2
- d. Infinity

494. In transmission lines, the most desirable reflection coefficient is

- a. Zero
- b. 0.5
- c. 1
- d. Infinity

495. At very high frequencies, transmission lines are used as _____.

- a. Tuned circuits
- b. Antennas
- c. Insulators
- d. Resistors

496. What is the reflection coefficient of a 100 ohm characteristic impedance line and a 300 ohm load?

- a. 0.25
- b. 0.3
- c. 0.5
- d. 0.75

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

- a. 0.67
- b. 1.0
- c. 1.2
- d. 1.5

498. A single conductor running from the transmitter to the antenna

- a. RG-8/U
- b. Single line wire
- c. Twin-lead
- d. Microstrip

499. What characteristic impedance is needed to match a 50-ohm line to a 300 ohm-load?

- a. 221 ohms
- b. 122 ohms
- c. 212 ohms
- d. 112 ohms

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

- a. Short circuit
- b. A complex impedance
- c. An open circuit
- d. A pure reactance

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