Electronics and Communication Engineering - Electromagnetic Field Theory

16.
A uniform plane wave travelling in air is incident on the plane boundary between air and another dielectric medium with εr = 4. The reflection coefficient for the normal incidence is
zero
0.5 ∠180°
0.33 ∠0°
0.33 ∠180°
Answer: Option
Explanation:

Reflection coefficient

.


17.
A transmission line has characteristics impedance of (75 + j 0.01) Ω and is terminated in a load impedance of (70 + j 50) Ω. The transmission coefficient will be
1.70 - j 2.97
0.08 + j 0.32
1.32 + j 1.38
1.08 + j 0.32
Answer: Option
Explanation:

Transmission coefficient .


18.
Maximum effective aperture of an antenna which is operating at a wavelength of 3 meters and has a directivity of 100
71.68 m2
716 m2
7.16 m2
71.6 m2
Answer: Option
Explanation:

.


19.
The distance between maxima and minima of a standing wave is
λ/4
λ/2
λ
Answer: Option
Explanation:


20.
A TV. transmitting aerial is fixed on top of a 150 metre tower located on a mountain 1200 m height. The range of transmitter is
51 km
152 km
152 m
51 m
Answer: Option
Explanation:

1 = 1.44[ht + ht]