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introduction to electromagnetic field
theory Hello everyone
I welcome all the viewers of this
video on electromagnetic field  this
video is the first from the series of
lectures for the pose electromagnetic
field theory aimed at engineering
students at undergraduate level in this
first video lecture I will like to bring
before you the points what is
electromagnetic field the inspirations
behind electromagnetic field theory why
we should be studying this subject and
the broad line the broad themes that we
are going to follow in the entire
duration of this course
so the first point what is
electromagnetic field
electromagnetic field is the physical
field produced by charged particles as
we see the term electromagnetic it has
two parts electric and magnetic see the
term can be splitted into two fields
electric field and magnetic field
electric field is produced because of
static charges whereas the magnetic
field is produced because of the charges
moving what we exactly all decks current
as the boss for both electric field and
magnetic field is same it is necessary
to study both the fields together with
an electromagnetic field
hence electromagnetic field theory can
be defined as the study hall electric
and magnetic field subject to the state
of the source
do you know if we hear the word killer
trick fill the scenario before us is
that there it is a certain charge
whether the charge may be positive or
negative and the region increased
because of that particular charge we
call that region as electric field in
this diagram we see the two charges
denoted by positive Q and negative Q the
lines what we term as electric flux
lines are always going away from the
positive charge whereas in the case of
negative charge these lines are always
coming towards it so a node can be done
that the electric flux lines are always
generated on positive charge whereas
they anymore negative charge okay so
this is a general representation or
general understanding of electric field
now regarding magnetic field always the
picture comes to into the mind is that
of bar magnet in this diagram the bar
magnet having two poles north and south
is shown the bar magnet is also
surrounded by some lines what we call
magnetic flux lines here also the
magnetic flux lines always originate at
the North Pole and the L upon the South
Pole now in case of charged particles
kill the charge is steady condition we
say produces electric field whereas when
it is in dynamic condition when it is in
motion we say this flow of current so if
we have a conductor flowing current in
particular direction so that cannot
conductor will be sounded by the
magnetic flux lines in this diagram
upright conductor is shown the current
in the upward direction it is surrounded
by the magnetic flux lines
the orientation of magnetic flux lines
is always determined according to the
right-hand thumb rules come in the
direction of current and the current
fingers gives you the direction of
magnetic plus now these are two examples
has given us the scenario of electric
field and magnetic field separately now
electromagnetic field together the
common example we have is
electromagnetic wave the light what we
get from Sun or from any source is
basically electromagnetic wave so let us
see electromagnetic wave
this is a diagram where the
representation of electromagnetic view
simply you move is shown in
three-dimensional space here the
coordinate axis r3 and data mutually
perpendicular to each other electric
field valleys in this diagram in
vertical plane whereas magnetic field
varies in the horizontal plane the third
direction shown by this axis Meuse you
the direction of propagation of will now
let us focus on to the second point what
are the inspirations behind the research
and development in the field of
electromagnetic fields here
see electromagnetic field is the
fundamental force in the nature like
gravitational force whatever the
naturally happening processes we see
which transform energy from one form to
another form these actually is the
biggest inspiration behind the research
and development rather the curiosity of
the by the scientists in this domain
okay the example is lightining 19th
century the experiments resulting into
the experience of magnetic field
surrounded to the electricity and some
similar experiences have given the
direction to the scientists like Faraday
ampere Maxwell Thomson green and Hertz
to work consistently into this field now
let us talk about the next point why we
should be studying this subject
electromagnetic 15 the first reason is
electromagnetic field is all around us
the second well all the electric or
electronic devices what we use for
example if you switch on any device or
if we press a key onto the keyboard
electromagnetic field comes in to zero
the basic principle of all such devices
is governed by four mathematical
equation i family will turn it iman
trois which is known as Maxwell's
equation these are not only just for
mathematical relations but they have the
complete summary behavior of electric
and magnetic field which is responsible
for the application to work the next
thing the electromagnetic field theory
if the research and development in this
area would not have been done we would
all have been in the dark ages there
would not be any kind of communication
or computer to work with and made yzma
this work lastly this subject is
important for scoring University
examinations gave examination IES
and other PSV examinations so learning
this subject is very very important now
finally we are going to see what are the
broad themes of the subject
electromagnetic field thing the complete
syllabus wok electromagnetic field
theory can be categorized into the
following four are themes that are
namely vector analysis electrostatics
steady magnetic fields Maxwell's
equations and time varying analysis
electromagnetic wave propagation through
different Vidya radiation and basics of
antenna most of the times engineering
students find electromagnetic subject to
be the killer subject but I assure you
the concepts in this particular subject
are very very simple to understand as
compared to other engineering core
subjects only the thing to get master
into the subject is to have curiosity
motivations and consistent practice
thank you
