IndiaBIX

Electronics and Communication Engineering - Electromagnetic Field Theory

Exercise : Electromagnetic Field Theory - Section 1
41.
A transmission line is feeding 1 watt of power to a horn antenna having a gain of 10 dB. The antenna is matched to the transmission line. The total power radiated by the horn antenna into the free space is
10 watts
1 watt
0.1 watt
0.01 watt
Answer: Option
Explanation:

= 101 Pr = 10 watt.

42.
A parallel polarized wave is incident from air into paraffin having relative permittivity 3, the value of its Brewster angle is
0°
30°
45°
60°
Answer: Option
Explanation:

Brewster angle θ = tan-1 .

43.
In a conductor which of the following relations hold good?
∇ x D = r
∇ . D = r
∇ x D = 0
∇ . D = 0
Answer: Option
Explanation:

Inside a conductor free charge is zero, hence, ∇ x D = 0.

44.
The radiation resistance of a λ/16 wire dipole in free space will be nearly
1 Ω
3 Ω
13 Ω
30 Ω
Answer: Option
Explanation:

Rr = 80p2.

45.
Two identical antennas are placed in the θ = p/2 plane as shown in the figure. The elements have equal amplitude excitation with 180° polarity difference, operating of the far-zone resultant electric field strength normalized with that of a single element, both computed for φ = 0, is
Answer: Option
Explanation:

Normalised array factor = n cos

where φ is the phase difference.

φ = (βd sin θ cos φ + θ1)

and θ = 90°, φ = 45°

Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers