Electronics and Communication Engineering - Electromagnetic Field Theory

31. 

Calculate the wave impedance for TM mode in rectangular waveguide for dominant mode at 3 GHz having

A. (120p) Ω
B. 377 Ω
C. 226 Ω
D. 629 Ω

Answer: Option C

Explanation:

η = 226 Ω.


32. 

The divergence of the electric field intensity at any point equals

A. 1/4 pε0 times the volume charge density
B. l/ε0 times the volume charge density at that point
C. ε0 times the volume charge density at that point
D. the volume charge density at that point

Answer: Option B

Explanation:


33. 

For a 400 kHz transmission line having L = 0.5 mH/km, C = 0.08 mF and negligible R and G, the value of propagation constant P will be

A. 15.9 radians/km
B. 31.8 radians/km
C. 63.6 radians/km
D. 105.4 radians/km

Answer: Option A

Explanation:

γ = a + jβ, a = 0 β = ωLC.


34. 

The Depth of penetration of EM wave in medium having conductivity σ at a frequency of 1 MHz is 25 cm. The depth of penetration at a frequency of 4 MHz will be

A. 6.25 cm
B. 12.50 cm
C. 50 cm
D. 100 cm

Answer: Option B

Explanation:

Skin depth

δ2 = δ1/2 .


35. 

What is the characteristic impedance at 10 MHz?

A. 547.7 Ω
B. 54.7 Ω
C. 5.47 Ω
D. .547 Ω

Answer: Option A

Explanation:

, not depend upon frequency.