Introduction to Electromagnetic
Field
Chapter 5.1: Material media
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Dielectric, semiconductor and conductor explained in quantum physic
Conductor
Semiconductor
Normal condition
In electric field
The conduction current
Introduction to Electromagnetic
Field
Chapter 1: Introduction
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1
Textbooks
[1] Nannapaneni N. Rao, "Elements of Engineering
Electromagnetic", 6th edition, Prentice-Hall, 2004.
[2] Ng Nht nh and Trng Trng Tun M, Trng i
Introduction to Electromagnetic
Field
Chapter 2.2: Magnetic field
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Magnetism and electric: some similarities
2
Relation between magnetic and electric
A magnetic needle is deflected by an adjacent
electric current
Fara
Introduction to Electromagnetic
Field
Chapter 2.1: Electric field
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FIELD is a description of how a physical quantity varies
from one point to another in the region of the field and
with time.
2
Name
Description
Exampl
Introduction to Electromagnetic
Field
Chapter 4.2: Uniform plane wave
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Wave equation in free space:
B
H
E = t = t
H
2E
2
E =
(E) E = 2
t
t
H = J + D = E
t
t
In free space
D = E = = 0
J=0
2E
E = 2
t
2
Consider
Introduction to Electromagnetic
Field
Chapter 4.1: Maxwells equations in
differential form
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Problem with Maxwells equations in integral form: field properties at a
point in space and time?
E and H along a loop
B and D
Introduction to Electromagnetic
Field
Chapter 3.2: Amperes circuital law
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The original Amperes law
Bdl = I
0
C
Apply Biot Savarts law to find B of a filamentary current P1.44/73
B=
0 I
a
2 r
B along the circular loop
Introduction to Electromagnetic
Field
Chapter 3.3: Maxwells equations in
integral form
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Maxwells equations in integral form
d
C E dl = dt B dS
d
C H dl = J dS + dt D dS
S D dS = V dv
S B dS = 0
E: electric intensity (
Introduction to Electromagnetic
Field
Chapter 2.2b: Gausss law for magnetic
field
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Gausss law for magnetic field (and the magnetic
monopole)
S B dS = 0
Apply Gausss law in magnetic field to find B
z
P2.23/126
dS4
1
B
Introduction to Electromagnetic
Field
Chapter 3.1: Faradays law
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Faradays experiment on electro-magnetic
induction
Any surface bounded by the same border
Induced electro-motive force (emf): causes
electrons to flow
Introduction to Electromagnetic
Field
Chapter 2.1b: Gausss law for electric
field
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Electric flux: the amount
of electric field passing
through a surface
Electric flux of charge Q:
the amount of electric
field passing