Electromagnetic Field Theory - Section 1 (4)

Directions to Solve

Electromagnetic Field Theory - Section 1

25.

A wave is propagated in a waveguide at frequency of 9 GHz and separation is 2 cm between walls calculate the phase velocity for dominant mode.

A.	3 x 10 8 m/sec
B.	5 x 10 8 m/sec
C.	1.5 x 10 8 m/sec
D.	9 x 10 8 m/sec

Answer: Option B

Explanation:

V_g . V_p = C²

26.

The electric field on the surface of a perfect conductor is 2V/m. The conductor is immersed in water with ε = 80 ε₀. The surface charge density on the conductor is ((ε₀ = 10^-9/36p)F/m)

A.	0 c/m2
B.	2 c/m2
C.	1.8 x 10-11 c/m2
D.	1.14 x 10-9 c/m2

Answer: Option D

Explanation:

214-212-1

214-212-2

27.

A plane wave is characterized by 194-210-1 the wave is

A.	linearly polarized
B.	circularly polarized
C.	elliptically polarized
D.	unpolarized

Answer: Option C

Explanation:

Because, magnitude is different (0.5, 1) and phase is 90°

28.

A (75 - j 40) W load is connected to a co-axial line of z₀ = 75ω at 6 MHz. The load matching on the line can be accomplished by connecting

A.	a short circuit stub at the load
B.	an inductance at the load
C.	a short circuit stub at a specific distance from the load
D.	a capacitance at a specific distance from the load

Answer: Option B

Explanation:

Z_L = 75 - J . 40, Z_C = 75 W, f = 6 mHz

Given Z_L is capacitive, so proper matching, load must be inductive.

29.

Most antenna consisting of a 50 meter long vertical conductor operates over a perfectly conducting ground plane. It is base fed at a frequency of 600 kHz. The radiation resistance of the antenna in ohms is