Electronics and Communication Engineering - Electronic Devices and Circuits

6. 

The temperature of cathode is increased from 2500K to 2600K. The increase in thermionic emission current is about

A. 0.1%
B. 4%
C. 50%
D. 150%

Answer: Option D

Explanation:

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7. 

Consider the following statement: At finite temperature, magnetic dipoles in a material are randomly oriented giving low magnetization. When magnetic field H is applied, the magnetization?

  1. Increases with H
  2. Decreases with H
  3. Decreases with temp for constant H
Which of the statement given above is/are correct?

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

Answer: Option D

Explanation:

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8. 

Ferrites have

A. low copper loss
B. low eddy current loss
C. low resistivity
D. higher specific gravity compared to iron

Answer: Option C

Explanation:

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9. 

Eg is the band gap, A is pre-factor, k is Boltzmann constant? Which one of the following is the remaining grade of paper used in paper capacitor, besides the other two grade of paper-low and extra low loss?

A. Strong dielectric
B. Regular
C. Rough
D. High loss

Answer: Option B

Explanation:

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10. 

Barkhausen criterion of oscillation is

A. Aβ > 1
B. Aβ = 1
C. Aβ = < 1
D. Aβ ≤ 1

Answer: Option B

Explanation:

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