85. Which of the following is a false statement? In case the SWR on a transmission line is infinity, the line is terminated in

A. a complex impedance

B. a pure reactance

C. a short circuit

D. an open circuit

86. A high frequency transmission line consists of a pair of open wires having a distributed capacitance of 0.01 itF per km and a distributed inductance of 3 mH per kmWhat is the characteristic impedance at 10 MHz?

A. 547.7 fi

B. 54.7 SI

C. 5.47 SZ

D. 0.547 ki.2

87. A high frequency transmission line consists of a pair of open wires having a distributed capacitance of 0.01 itF per km and a distributed inductance of 3 mH per km What will be the propagation constant at 10 MHz?

A. 3.4 radians/km

B. 34.4 radians/km

C. 344 radians/km

D. 3440 radians/km

88. Which type of transmission line will have the least characteristic impedance?

A. Open wire line

B. Twin lead line

C. Coaxial cable

D. All have same impedance

89. The phase angle corresponding to ? in a standing-wave pattern is

A.300

B.900

C. 135?

D. 180?

90. Waveguide are used mainly for microwave signal because

A.they depend on straight-line propagation which applies to microwave only

B.losses would be too heavy at lower frequency

C. there are no generators powerful enough to excite them at lower frequencies

D. they would be too bulky at lower frequencies

91. The wavelength of a wave in a waveguide is greater than in free space

A.depends on the wavelength dimensions and the free space wavelength

B. is inversely proportional to the phase velocity

C. is inversely proportional to the phase velocity

D. is directly proportional to the group velocity

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