# Electronics and Communication Engineering - Microwave Communication

### Exercise :: Microwave Communication - Section 5

46.

Oscillations are obtained from a reflex klystron only for combinations of anode voltage and repeller voltage that give a favourable transit time.

 A. True B. False

Answer: Option A

Explanation:

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47.

In the given figure shows a 10dB directional coupler. If power input at port 1 is 100 mW, power output at port 3 is A. 10 mW B. 15 mW C. 20 mW D. 25 mW

Answer: Option A

Explanation:

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48.

The noise figure of klystron amplifier is about

 A. 25 dB B. 3 dB C. zero D. 1 dB

Answer: Option A

Explanation:

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49.

Which one of the following is true for EM wave propagation through rectangular waveguide of cross-section 2a x a

 A. critical wavelength for TE10 mode is the same as that for TE02 mode B. critical wavelength for TE10 mode is one half of that for TE10 mode C. critical wavelength for TE10 mode is the same as that for TM10 mode D. critical wavelength for TE10 mode is double that for TE01mode

Answer: Option C

Explanation:

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50.

In the given figure the line voltage after a number of reflections will be A. 30 V B. -30 V C. 10 V D. -10 V

Answer: Option C

Explanation:

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