120. The largest application of microwaves is in
A. industrial heating
B. research
C. cooking
D. communications
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
122. The parametric amplifier has ____ gain and low noise figure
A. medium
B. negligible
C. low
D. high
123. Which is the cross field device?
A. Magnetron
B. Reflex klystron
C. Two cavity klystron
D. Travelling wave tube
124. Which of the following microwave diodes is suitable for very low power oscillators?
A. GUNN
B. LSA
C. IMPATT
D. TUNNE1
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
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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