64. A transmision line of length nA./4 (n is integer) is short circuited at the far end. The input impedance is
65. A transmission line of length / < A./4 is open circuited at the far end. The input impedance is
66. A transmission line of length / < ?4 is at the far end. The input line is required to match over a wide frequency
67. A transmission with the load radiates energy
A. in a well defined direction.
B. uniformally in all directions.
C. inside a hollow sphere.
D. uniformally in horizontal plane.
68. To couple a coaxial line to a parallel wire line, it is best to use
A. a balun
B. a slotted line
C. a directional coupler
D. a quarter wave line
69. Radiation resistance of a halfwave dipole is
70. Main drawback of a two hole directional coupler is its
A. poor directirity
B. narrow bandwidth
C. poor directional coupling
D. high standing wave ratio
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