One of the reasons why vacuum tubes eventually fail at microwave frequ

1.	One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their:
A.	Noise figure increases
B.	Transit time beomes too short
C.	Shunt capacitive reactances become too large
D.	Series inductive reactances become too small
Answer» B. Transit time beomes too short

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One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their:

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