Electronics and Communication Engineering - Exam Questions Papers

16. 

Consider the transmission line of length 37.5 cm, which is terminated into zero resistance. This line is being exited by a source of 1 GHz which has an internal impedance of 50 Ω. What is the input impedance of the line as seen by the source?

A. 50 Ω
B. Zero Ω
C. 100 Ω
D. Infinite Ω

Answer: Option D

Explanation:

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17. 

The junction capacitance of a linearly graded pn junction (with applied voltage = VB) is proportional to

A.
B.
C.
D.

Answer: Option D

Explanation:

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18. 

Consider the following statements:
For a square waveguide of cross-section 3m x 3m it has been found

  1. At 6 GHz dominant mode will propagate
  2. At 4 GHz only dominant modes and evanescent
  3. At 11 GHz all the modes and no higher order mode will propagate
  4. At 7 GHz degenerate modes will propagate
Which of the above statements are correct?

A. 1 and 2 only
B. 1, 2 and 4
C. 2 and 3 only
D. 2, 3 and 4

Answer: Option A

Explanation:

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19. 

The circuit shown depicts :

A. voltage series negative feedback
B. voltage shunt negative feedback
C. current series negative feedback
D. current shunt negative feedback

Answer: Option D

Explanation:

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20. 

Which of the transistor models is most preferred for the analysis of a transistor circuit both at mid-band and at high frequencies?

A. h-parameter model
B. y-parameter model
C. s-parameter model
D. hybrid-p model

Answer: Option D

Explanation:

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