78. for frequencies unto GHz range
A. remains constant
B. is increased
C. is decreased
D. first increases and then decreases

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79. Which of the following materials can be used to make a light-emitting diode?
A. Silicon
B. Germanium
C. Gallium arsenide
D. Phosphorescent material

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80. Regarding a Schottky diode which of the following statements is incorrect?
A. It is a bipolar device
B. has fast recovery time
C. has no depletion layer
D. has metal-semiconductor junction

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81. The microwave device used as an oscillator within the frequency range 10-1000 GHz is
A. step recovery diode
B. Gunn diode
C. Schottky diode
D. IMPATT diode

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82. Which of the following statements is correct regarding a step-recovery diode?
A. It is an ideal rectifier of high frequency signals
B. It has an extremely short recovery time
C. It conducts equally well in both directions
D. It is mainly used as a harmonic generator

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83. A PIN diode is frequency used as a
A. harmonic generator
B. peak clipper
C. voltage regulator
D. switching diode

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84. The minimum number of diodes needed for a bridge rectifier is
A. eight
B. four
C. two
D. one

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