## Electromagnetic Engineering - May 2015

### Electronics Engineering (Semester 5)

TOTAL MARKS: 80

TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.

(2) Attempt any **three** from the remaining questions.

(3) Assume data if required.

(4) Figures to the right indicate full marks.

### Attempt any four:

**1 (a)** Point charges Q_{1}=300° C located at (1,-1,3)m experiences a force $$ \overline{F1}=\overline{8ax}-\overline{8ay}+\overline{4az} N$$ due to point charge Q_{2} at (3,-3,-2)m. Determine Q_{2}.(5 marks)
**1 (b)** Explain isotropic, omnidirectional and directional antenna with suitable examples.(5 marks)
**1 (c)** Compare MOM, FEM and FDM.(5 marks)
**1 (d)** Find out the divergence and curl of the following function $$ \overline{A}=2xy \overline{ax} + (x^2z) \overline{ay}+z^3 \overline{az} $$(5 marks)
**1 (e)** Explain skip distance with the formula.(5 marks)
**2 (a)** Derive Maxwell's integral and point form equation for static fields.(10 marks)
**2 (b)** Find electric field intensity E due to an infinite line charge carrying current I.(10 marks)
**3 (a)** Define the polarization of wave. Explain different types of polarization.(10 marks)
**3 (b)** Derive wave equations for free spacing for conducting media.(10 marks)
**4 (a)** Explain in detail FDM method also state advantages and drawback of it.(10 marks)
**4 (b)** State and derive the poynting theorem and describe the significance of each term.(10 marks)
**5 (a)** Explain the significance of the term 'effective area of an antenna'. Derive the relationship between effective area and directivity of any antenna.(10 marks)
**5 (b)** Explain the principle modes of operation of helical antenna and draw its radiation pattern.(10 marks)

### Attempt any two:

**6 (a)** Classify and explain different types of wave propagation.(10 marks)
**6 (b)** Explain folded dipole antenna and its applications.(10 marks)
**6 (c)** Explain following terms critical frequency, virtual height, maximum usable frequency.(10 marks)