This is the Multiples Choice Questions Part 1 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.

### 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**

### Start Practice Exam Test Questions Part I of the Series

1. What is the opposition to the transfer of energy which is considered the dominant characteristic of a cable or circuit that emanates from its physical structure?

- a. Conductance
- b. Resistance
- c. Reactance
- d. Impedance

2. When load impedance equals to Zo of the line, it means that the load _____ all the power.

- a. reflects
- b. absorbs
- c. attenuates
- d. radiates

3. impedance matching ratio of a coax balun.

- a. 1:4
- b. 4:1
- c. 2:1
- d. 3:2

4. Which stands for dB relative level?

- a. dBrn
- b. dBa
- c. dBr
- d. dBx

5. Standard test tone used for audio measurement.

- a. 800 Hz
- b. 300 Hz
- c. 100 Hz
- d. 1000 Hz

6. When VSWR is equal to zero, this means

- a. that no power is applied
- b. that the load is purely resistive
- c. that the load is a pure reactance
- d. that the load is opened

7. _______ is the ratio of reflected voltage to the forward travelling voltage.

- a. SWR
- b. VSWR
- c. Reflection coefficient
- d. ISWR

8. Transmission line must be matched to the load to ______.

- a. transfer maximum voltage to the load
- b. transfer maximum power to the load
- c. reduce the load current
- d. transfer maximum current to the load

9. Which indicate the relative energy loss in a capacitor?

- a. Quality factor
- b. Reactive factor
- c. Dissipation factor
- d. Power factor

10. What is the standard test tone?

- a. 0 dB
- b. 0 dBW
- c. 0 dBm
- d. 0 dBrn

11. The energy that neither radiated into space nor completely transmitted.

- a. Reflected waves
- b. Captured waves
- c. Incident waves
- d. Standing waves

12. Micron is equal to _______ meter.

- a. 10-10
- b. 10-9
- c. 10-6
- d. 10-3

13. 1 Angstrom (A) is equal to _______.

- a. 10-3 micron
- b. 10-10 m
- c. 10-6 micron
- d. 10-6 m

14. Why is it impossible to use a waveguide at low radio frequencies?

- a. Because of the size of the waveguide
- b. Due to severe attenuation
- c. Due to too much radiation
- d. All of these

15. ________ is the transmission and reception of information.

- a. Modulation
- b. Communications
- c. Radiation
- d. Emission

16. What is the loss of the circuit in dB if the power ration of output to input is 0.01?

- a. 20
- b. -20
- c. 40
- d. -40

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

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

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

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

19. ________ is the advantage of the balanced transmission line compared to unbalanced line.

- a. Low attenuation
- b. Easy installation
- c. Low radiation loss
- d. Tensile strength

20. _______ is the method of determining the bandwidth of any processing system.

- a. Fourier series
- b. Spectral analysis
- c. Frequency analysis
- d. Bandwidth analysis

21. What causes the attenuation present in a waveguide?

- a. The air dielectric filling the guide
- b. The coating of silver inside
- c. Losses in the conducting walls of the guide
- d. Radiation loss

22. A device that converts a balanced line to an unbalanced line of a transmission line.

- a. Hybrid
- b. Stub
- c. Directional coupler
- d. Balun

23. What is the approximate line impedance of a parallel-strip line spaced 1 cm apart with the length of 50 cm?

- a. 10 ohms
- b. 15 ohms
- c. 18 ohms
- d. 23 ohms

24. What is the average power rating of RG-58 C/u?

- a. 25 W
- b. 50 W
- c. 75 W
- d. 200 W

25. A coaxial cable used for high temperatures.

- a. RG-58C
- b. RG-11A
- c. RG-213
- d. RG-211

26. If you have available number of power amplifiers with a gain of 100 each, how many such amplifiers do you need to cascade to give an overall gain of 60dB?

- a. 2
- b. 3
- c. 4
- d. 5

27. You are measuring noise in a voice channel at a -4 dB test point level, the meter reads -73 dBm, convert the reading into dBrnCO.

- a. 12
- b. 16
- c. 18
- d. 21

28. The velocity factor for a transmission line

- a. depends on the dielectric constant of the material used
- b. increases the velocity along the transmission line
- c. is governed by the skin effect
- d. is higher for a solid dielectric than for air

29. Impedance inversion can be obtained by

- a. a short-circuited stub
- b. an open-circuited stub
- c. a quarter-wave line
- d. a half-wave line

30. Transmission lines when connected to antennas have

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

31. One of the following is not a bounded media.

- a. Coaxial line
- b. Two-wire line
- c. Waveguide
- d. Ocean

32. The impedance measured at the input of the transmission line when its length is infinite.

- a. Input impedance
- b. Open circuit impedance
- c. Characteristic impedance
- d. Short circuit impedance

33. The following are considered primary line constants except

- a. conductance
- b. resistance
- c. capacitance
- d. complex propagation constant

34. The dielectric constants of materials commonly used in transmission lines range from about

- a. 1.2 to 2.8
- b. 2.8 to 3.5
- c. 3.5 to 5.2
- d. 1.0 to 1.2

35. Typically, the velocity factor (VF) of the materials used in transmission lines range from

- a. 0.6 to 0.9
- b. 0.1 to 0.5
- c. 1.0 to 0.9
- d. 0.6 to 0.8

36. For an air dielectric two-wire line, the minimum characteristic impedance value is

- a. 85 ohms
- b. 85 ohms
- c. 90 ohms
- d. 88 ohms

37. When a quarter-wave section transmission line is terminated by a short circuit and is connected to an RF source at the other end, its input impedance is

- a. inductive
- b. capacitive
- c. resistive
- d. equivalent to a parallel resonant LC circuit

38. A transmitter operating at 30 MHz with 4 W output is connected via 10 m of RG-8A/u cable to an antenna that has an input resistance of 300 ohms. Find the reflection coefficient.

- a. 0.71
- b. 0.77
- c. 0.97
- d. 0.76

39. A quarter wave transformer is connected to a parallel wire line in order to match the line to a load of 1000 ohms. The transformer has a characteristic impedance of 316.23 ohms. The distance between centers is 4 inches. What is the percentage reduction in the diameter of the line?

- a. 85%
- b. 83%
- c. 86%
- d. 90%

40. The concept used to make one Smith chart universal is called

- a. ionization
- b. normalization
- c. rationalization
- d. termination

41. What are the basic elements of communications system?

- a. Source, transmission channel, transmitter
- b. Transmitter, receiver, transmission channel
- c. Information, transmission channel, receiver
- d. Sender and receiver

42. ________ is the transmission of printed material over telephone lines.

- a. Internet
- b. Data communication
- c. Telegraphy
- d. Facsimile

43. ________ is a continuous tone generated by the combination of two frequencies of 350 Hz and 440 Hz used in telephone sets.

- a. DC tone
- b. Ringing tone
- c. Dial tone
- d. Call waiting tone

44. ________ are unidirectional amplifiers having 20-25 decibel gain that are placed about 75 km apart used to compensate for losses along the telephone line.

- a. VF repeaters
- b. Loading coils
- c. Loop extenders
- d. Echo suppressors

45. ________ is a component in the telephone set that has the primary function of interfacing the handset to the local loop.

- a. Resistor
- b. Capacitor
- c. Varistor
- d. Induction coil

46. Pulse dialing has ________ rate.

- a. 20 pulses/min
- b. 10 pulses/min
- c. 10 pulses/sec
- d. 80 pulses/sec

47. ________ is a telephone wire that connects two central offices.

- a. 2-wire circuit
- b. Trunk line
- c. Leased line
- d. Private line

48. The central switching office coordinating element for all cell sites that has cellular processor and a cellular switch. It interfaces with telephone company zone offices, control call processing and handle billing activities.

- a. MTSO
- b. Cell site
- c. PTSN
- d. Trunk line

49. ________ in a cellular system performs radio-related functions for cellular site.

- a. Switching system
- b. Base station
- c. Operation and support system
- d. Mobile station

50. A technology used to increase the capacity of a mobile phone system.

- a. Frequency re-use
- b. Cell splitting
- c. TDM
- d. FDM