Jawaharlal Nehru Technological University Kakinada 2008 B.Tech Electrical and Electronics Engineering ELECTROMAGNETIC FIELDS - Question Paper

has a voltage 50 Sin 103
t volts applied to its plates. compute the displacement
current, assuming e= 2e0. [8+8]
? ? ? ? ?









2 of 2Code No: 07A3EC04 Set No. 2
II B.Tech I Semester Regular Examinations, November 2008
ELECTROMAGNETIC FIELDS
( Common to Electrical & Electronic Engineering and Electronics & Control
Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
? ? ? ? ?
1. (a) Derive the concept of electric ?eld intensity from Columb’s legal regulations.
(b) Derive an expression for electric ?eld intensity at any point ‘P’ at a radial
height ‘h’ from a ?nite line charge of ? c/m. extending along the z-axis from
32 to 33 distance ‘P’ in the x-y plane. [8+8]
2. Establish Gauss legal regulations in point form and integral form hence deduce the Laplace‘s
and Poissions‘s equations. [16]
3. A parallel plate capacitor has a plate area of 1.5 Sq.m. and a plate separation of
5 mm. There are 2 dielectrics in ranging from the plates. The ?rst dielectric has a
thickness of three mm with a relative permittivity of six and the 2nd has a thickness
of two mm with relative permittivity 4. obtain the capacitance . Derive the formula
uses. [16]
4. A single-phase circuit comprises 2 parallel conductors A and B, every one cm diam-
eter and spaced one m apart. The conductors carry current of +100 and -100 Amps.
respectively. Determine the ?led intensity at the surface of every conductor and also
in space exactly midway ranging from A and B. [16]
5. (a) Using Amperes circuital law, find an expression for the magnetic ?eld in-
tensity at any point due to a concentric cylindrical conductors, the inner and
outer conductors carrying equal and opposite currents.
(b) Using amperes circuital law, ?nd H and B inside a long straight non magnetic
conductor of radius eight mm carrying a current density of 50 kA/m2
[16]
6. (a) Show that T = m B also holds for the torque on a solenoid situate in a uniform
magnetic ?eld.
(b) i. What is the maximum torque on a square loop of 1000 turns in a ?eld
of uniform ?ux density B Tesla? The loop has 10cm side and carries a
current of 3A.
ii. What is the magnetic moment of the loop? [8+8]
7. (a) Derive an expression for energy density in a magnetic ?eld.

Earning:   Approval pending.