Electronics and Communication Engineering - Electromagnetic Field Theory MCQs Part 9

1.Television receiver antenna is usually

A. loop type
B. yagi antenna
C. parabolic dishes
D. none of the above

 Answer Option B

2.In figure the current distribution is represented by

A. curve A
B. curve B
C. curve C
D. curve D

 Answer Option C

3.Half power point directions for broadside is

A. 60°
B. 30°
C. 45°
D. at any angle

 Answer Option A

4.What will happen to a bird sitting on a conductor?

A. It will die of shock
B. It will not die of shock because its claws are insulated
C. It will not die because it is insulated from earth and other conductors
D. None of the above

 Answer Option C

5.Which one is correct option?

A. Phase velocity is greater than light velocity
B. Group velocity is greater than light velocity
C. Phase velocity is equal to group velocity
D. Phase velocity is less than light velocity

 Answer Option A

6.Given that , if the radiation intensity of an antenna is proportional to sin2 θ, where θ is the elevation angle, the antenna directivity will be

A.
B.
C.
D.

 Answer Option D

7.The term critical frequency denotes

A. the lowest frequency that is reflected by the ionosphere
B. the highest frequency that is reflected by the ionosphere at vertical distance
C. the lowest frequency by which communication is possible between two given points
D. none of the above

 Answer Option B

8.The important postulate arising out of Maxwell's modification of Ampere's law is

A. a changing magnetic field produces an electric field
B. a changing electric field produces a magnetic field
C. a motional e.m.f. is produced by a coil moving in a magnetic field
D. a steady current produce a magnetic field

 Answer Option B

9.Which of the following is not a wideband antenna?

A. Marconi
B. Discone
C. Helical
D. Folded dipole

 Answer Option A

10.The polarization phenomena in Faraday rotation

A. is non-reciprocal
B. exists along perpendicular direction
C. exists along the axis of array
D. does not exist

 Answer Option A

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