8/4/2019 emf 6
4/4
Code No: X0225/R07
II B.Tech I Semester (R07) Regular Examinations, Nov- 2010
ELECTRO MAGNETIC FIELDS
(Electrical & Electronics Engineering)
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
1. a) State Coulombs law of force between any two point charges
and state the units ofquantities
b) Find the electric field at any point between the two
concentric spherical shells, inner
spherical shell has charge Q1 and outer spherical shell has
charge Q2.
2. a) Derive the expression for torque on an electric dipole in
an electric fieldb) In cylindrical coordinates, V= 60V at =6 mm and
V=0 at =66 mm. Find the voltage
at =140 mm, if the potential depends only on .
3. a) Derive the ohms law in point formb) Deduce an expression
for the joint capacitance of two capacitors C1 and C2i) In series
and
ii) In parallel. If C1=100 ,50, 2 FCF = calculate
iii) The joint capacitance and
iv) The total energy stored with a steady applied P.D. of 1000
V, in each case.
4. a) Using Biot-savart law, find Hon axis of circuits loopb) A
steady current of I amperes flow in a conductor bent in the form of
square loop of side
a. Find magnetic field intensity at the centre of the loop.
5.
a) Derive the Maxwells third equationb) Obtain the expression
for H in all the regions if a cylindrical conductor carries a
direct
current I and its radius is R m. Plot the variation ofH against
the distance r from the
centre of the conductor.
6. a) Define magnetic dipole? What is magnetic moment? Discuss
how a differential currentloop behaves like a magnetic dipole
b) Two long parallel conductors carry 80 A. If the conductors
are separated by 30 mm.
Find the force per metre of each conductor, if the current flow
is in opposite direction.
7. a) Derive the expression for mutual inductance using Neumanns
formulab) A solenoid with 300 turns is 300 mm long and 30 mm in
diameter. If the current is 500
mA, find i) Inductance and ii) energy stored in solenoid. Assume
1=r
8. a) Write and explain differential and integral forms of
Maxwells equations for fieldsvarying hormonally with time
b) Find the frequency at which conduction current density and
displacement current density
are equal in a medium with .811024
==
randmho
1 of 1
SET - 4
ase purchase PDF Split-Merge on www.verypdf.com to remove this
watermark.
