13. If the length of a section of RG-59 coaxial cable is doubled, its velocity factor will:
a. increase.
b. decrease.
c. remain the same.
Answer: c
14. A transmission line that is terminated with a resistive load that is equal to the characteristic impedance of the line is called:
a. reactive.
b. resonant.
c. lossy.
d. nonresonant.
Answer: d
15. A transmission line that is terminated with an impedance that is not equal to its characteristic impedance is called:
16. A transmission line having a delay time of 45 microseconds and terminated with an open is applied with a 4 VDC incident voltage. At the load end of the line:
a. the voltage changes from 0V to 8V at t = 45 microseconds.
b. the voltage changes from 0V to 4V at t = 45 microseconds.
c. the voltage changes from 0V to –4V at t = 45 microseconds.
d. the voltage changes from 0V to 8V to t = 90 microseconds.
e. the voltage changes from 0V to 4V at t = 45 microseconds.
Answer: a
17. A non-lossy transmission line terminated with an open circuit will have:
a. an in-phase reflected voltage that is equal in magnitude to the incident voltage.
b. an opposite-phase reflected voltage that is equal in magnitude to the incident voltage.
c. an in-phase reflected voltage that is smaller in magnitude than the incident voltage.
d. an opposite-phase reflected voltage that is smaller in magnitude than the incident voltage.
Answer: a
18. A non-lossy transmission line terminated with an open circuit will have:
a. an in-phase reflected current that is equal in magnitude to the incident current.
b. an opposite-phase reflected current that is equal in magnitude to the incident current.
c. an in-phase reflected current that is smaller in magnitude than the incident current.
d. an opposite-phase reflected current that is smaller in magnitude than the incident current.
TEST ITEM FILE – Chapter 12
19. A non-lossy transmission line terminated with a short circuit will have:
a. an in-phase reflected current that is equal in magnitude to the incident current.
b an opposite-phase reflected current that is equal in magnitude to the incident current.
c. an in-phase reflected current that is smaller in magnitude than the incident current.
d. an opposite-phase reflected current that is smaller in magnitude than the incident current.
Answer: a
20. A transmission line terminated with an open has a VSWR of:
a. –1.
b. 0.
c. +1.
d. infinity.
Answer: d
21. A transmission line terminated with a short has a VSWR of:
a. –1.
b. 0.
c. +1.
d. infinity.
Answer: d
22. A transmission line terminated with a load resistance that is equal to the transmission line's characteristic impedance has a VSWR of:
a. –1.
b. 0.
c. +1
d. infinity.
Answer: c
23. A transmission line terminated with an open has a reflection coefficient at the load of:
a. –1.
b. 0.
c. +1.
d. infinity.
Answer: c
24. A transmission line terminated with a short has a reflection coefficient at the load of:
a. –1.
b. 0.
c. +1
d. infinity.
Answer: a
TEST ITEM FILE – Chapter 12
25. A transmission line terminated with a load resistance that is equal to the transmission line's characteristic impedance has a reflection coefficient at the load of:
a. –1.
b. 0.
c. +1.
d. infinity.
Answer: b
26. A 50 ohm transmission line that has a load impedance of 300 ohms has a reflection coefficient of:
27. The disadvantage of not having a perfectly matched transmission line in a communication system is:
a. the fully generated power does not reach the load.
b. the cable dielectric may break down.
c. the existence of reflections increases the power loss.
d. noise problems are increased.
e. none of the above.
Answer: e
28. The input impedance of a quarter-wavelength section of 50 ohm transmission line that is terminated with an open is:
a. 50 ohms.
b. 0 ohms (a short).
c. infinite (open).
d. 100 ohms.
Answer: b
29. The input impedance of a half-wavelength section of 50 ohm transmission line that is terminated with a short is:
a. 50 ohms.
b. 0 ohms.
c. infinite (open).
d. 100 ohms.
Answer: b
TEST ITEM FILE – Chapter 12
30. The input impedance of a half-wavelength section of 50 ohm transmission line that is terminated with an open is:
a. 50 ohms.
b. 0 ohms (a short).
c. infinite (open).
d. 100 ohms.
Answer: c
31. Moving a full revolution around an SWR circle on the Smith chart represents:
a. moving a quarter-wavelength down the transmission line.
b. moving a half-wavelength down the transmission line.
c. moving a full wavelength down the transmission line.
d. moving two wavelengths down the transmission line.
Answer: b
32. The center of the Smith chart represents:
a. an open circuit load impedance.
b. a short circuit load impedance.
c. a matched load impedance.
d. a 1 ohm load impedance.
Answer: c
33. The perimeter of the Smith chart graph represents:
a. the SWR of a transmission line terminated with an open circuit.
b. the SWR of a transmission line terminated with a short circuit.
c. an infinite SWR circle.
d. all of the above.
Answer: d
34. A quarter-wavelength transmission line is terminated with a 300 ohm load. Its input impedance is 75 ohms. Its characteristic impedance is:
a. 50 ohms.
35. A pulse-technique used in determining the location of a fault in a transmission line is called:
a. slotted-line measurements.
b. SWR measurements.
c. time-domain reflectometry.
d. stub tuning.
Answer: c
TEST ITEM FILE – Chapter 12
36. Near-end crosstalk is best defined as
a. a measure of the level of crosstalk within a cable b. a measure of the signal coupling outside the cable c. a measue of the level in side the cable
d. a desired perormance objective e. none of the above
Answer: a
37. CAT 5e cable can handle a 100MHz bandwidth up to a length of:
a. 22 meters
38. Wiring of the RJ-45 connector CAT6 cable is defined by the telecommunications industry standard:
a. 802.3
b. attenuation and crosstalk.
c. crosstalk and PSNEXT d. CAT3 and CAT5 e. none of the above Answer: b
40. The CAT1 specification for twisted pair:
a. same as CAT3
TEST ITEM FILE – Chapter 12
41. An impedance value of Z11=1+j0 indicates it is:
a. capacitive b. inductive c. 50Ω
d. purely resistive e. none of the above Answer: d
42. The characteristic impedance of a network analyzer is set to 50Ω. A Z11=0.5+j0.5 translates to:
a. 25+j0 b. 50+j25 c. 25+j25 d. 25+j50 e. 50+j50 Answer: c
43. At resonance, a series RLC circuit will be:
a. resistive only b. capacitive only c. inductive only d. reactive
e. none of the above Answer: a