120. The largest application of microwaves is in
A. industrial heating
B. research
C. cooking
D. communications

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121. Microwave links are preferred for TV transmission because
A. they are free from impulse noise
B. they produce less phase distortion
C. they are cheaper
D. they have large bandwidth

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122. The parametric amplifier has ____ gain and low noise figure
A. medium
B. negligible
C. low
D. high

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123.  Which is the cross field device?
A. Magnetron
B. Reflex klystron
C. Two cavity klystron
D. Travelling wave tube

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124. Which of the following microwave diodes is suitable for very low power oscillators?
A. GUNN
B. LSA
C. IMPATT
D. TUNNE1

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125. Which of the following statement is not valid? A varactor diode may be useful at microwave frequencies
A. for electronic tuning
B. as an oscillator
C.as a parametric amplifier
D. for frequency multiplication

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126. The advantage of microwave over lower frequency signals is
A. increased bandwidth
B. ability to use high gain
C. increased secrecy
D. all of the above

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