Electronics and Communication Engineering - Exam Questions Papers

46. 

Consider the following statements:
In a microstrip line

  1. Wavelength , where eff is the effective dielectric constant and 1 is the free space wavelength.
  2. Electromagnetic fields exist partly in the air above the dielectric substrate and partly within the substrate itself.
  3. The effective dielectric constant is greater than the dielectric constant of the air.
  4. Conductor losses increase with decreasing characteristic impedance.
Which of the above statements is/are correct?

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

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

47. 

In the circuit below, if diodes and the moving coil millimeter are assumed to be ideal if mA reading is , find Vm.

A. 1 mV
B. 0.1 V
C. 0.1 mV
D. 1 V

Answer: Option D

Explanation:

Now,

Im = pIDC = 0.1 mA

Vm = Im x R = 0.1 mA x 10 K

Vm = 1 Volt.


48. 

What current does represent in pn junction diode? (where the symbols have their usual meaning)

A. Forward current
B. Diffusion current
C. Drift current
D. Reverse saturation current

Answer: Option D

Explanation:

No answer description available for this question. Let us discuss.

49. 

What happens when a paramagnetic material is heated above Curie temperature?

A. It becomes diamagnetic
B. It becomes nonmagnetic
C. It becomes ferromagnetic
D. It becomes anti-ferromagnetic

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

50. 

How many roots with positive real parts do the equation s3 + s2 - s + 1 = 0 have?

A. Zero
B. One
C. Two
D. Three

Answer: Option C

Explanation:

No answer description available for this question. Let us discuss.

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