Microwave Communication problems
- 1. The main advantage of TWT over klystron is
Options- A. higher bandwidth
- B. higher gain
- C. higher frequency
- D. higher output Discuss
Correct Answer: higher bandwidth
- 2. Fields are said to be circularly polarized if
Options- A. their magnitudes are equal
- B. their magnitudes are equal and they differ in phase by ± 90°
- C. their magnitudes are unequal and they differ in phase ± 90°
- D. their magnitudes are unequal and they are in phase Discuss
Correct Answer: their magnitudes are equal and they differ in phase by ± 90°
- 3. The frequency of oscillations obtained from a reflex klystron depends mainly on
Options- A. resonant frequency of cavity
- B. repeller voltage
- C. voltage of focussing electrode
- D. characteristics of cathode Discuss
Correct Answer: resonant frequency of cavity
- 4. Assertion (A): Two equal and opposite travelling waves result in a standing wave.
Reason (R): The ratio of maximum to minimum value of a standing wave is called SWR.
Options- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is correct but R is wrong
- D. A is wrong but R is correct Discuss
Correct Answer: Both A and R are correct but R is not correct explanation of A
- 5. In TE and TM modes of rectangular waveguides having propagation in z direction
Options- A. Ez and Hz are both zero
- B. In TE mode Ez is zero and in TM mode Hz is zero
- C. In TE mode Hz is zero and in TM mode Ez is zero
- D. In both TE and TM modes both Ez and Hz are non-zero Discuss
Correct Answer: In TE mode Ez is zero and in TM mode Hz is zero
- 6. Assertion (A): In circular waveguide the attenuation of TE01 mode decreases as the operating frequency increases.
Reason (R): The wall currents in a circular waveguide in TEQ1 mode are completely circumferential.
Options- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is correct but R is wrong
- D. A is wrong but R is correct Discuss
Correct Answer: Both A and R are correct but R is not correct explanation of A
- 7. When a wave reaches an open circuit
Options- A. the voltage at termination is doubled the incident voltage
- B. the current at termination is doubled the incident voltage
- C. the voltage at termination is zero
- D. both V and I at termination are doubled the incident voltage and current Discuss
Correct Answer: the voltage at termination is doubled the incident voltage
- 8. In a rectangular waveguide there is one half wave variation of electric field across the narrow dimension and two half wave variations of electric field across wider dimension. The dominant mode is
Options- A. TM12
- B. TE13
- C. TE21
- D. TM25 Discuss
Correct Answer: TE21
- 9. Wave guides are pressurised above normal atmospheric pressure for
Options- A. increasing the power handling capacity
- B. improving conductivity of walls
- C. preventing higher modes from propagation
- D. varying the wave impedance Discuss
Correct Answer: increasing the power handling capacity
- 10. Assertion (A): In a power divider SH = 0, S21 = 0.707 = S3,
Reason (R): In a power divider the input port (i.e., port 1) is matched and incident power is equally divided in output ports 2 and 3
Options- A. Both A and R are correct and R is correct explanation of A
- B. Both A and R are correct but R is not correct explanation of A
- C. A is correct but R is wrong
- D. A is wrong but R is correct Discuss
Correct Answer: Both A and R are correct and R is correct explanation of A
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