Electronics and Communication Engineering - Electromagnetic Field Theory

6. 

∇ . = 0 is frequently known as

A. continuity equation for steady currents
B. Laplace equation
C. Poisson's equation
D. none of the above

Answer: Option A

Explanation:

Equation of continuity

∇ x J = 0.


7. 

A rhombic antenna is a

A. resonant antenna
B. non-resonant antenna
C. coupled antenna
D. none of the above

Answer: Option B

Explanation:

No answer description available for this question. Let us discuss.

8. 

Which of the following relations is valid?

A. ∇ x ∇ x = ∇(∇ . ) - ∇2 A
B. ∇ x ∇ x = ∇(∇ x ) - ∇2 A
C. ∇ x ∇ x = ∇2 A - (∇)
D. none of the above

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

9. 

Diffraction of electromagnetic waves

A. may occur around the edge of a sharp obstacle
B. is caused by reflections from the ground
C. arises only with the spherical wave fronts
D. will occur when the waves pass through a large slot

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

10. 

The magnetic field intensity vector of a plane wave is given by (x, y, z, t) = 10 sin (5000t + 0.004x + 30 ), where denotes unit vector in y direction the wave is propagating with a phase velocity.

A. 5 x 104 m/sec
B. -3 x 108 m/sec
C. -1.25 x 107 m/sec
D. 3 x 108 m/sec

Answer: Option C

Explanation:

(x, y, z, t) = 10 sin (5000t + 0.004x + 30)

Wave is propagating in - ve direction, hence

v = - 1.25 x 107 m/sec.