Solenoid - Magnetic Effects of Current, CBSE Class 10 Physics Video Lecture

hello friends this video on magnetic
effects of current part 7 is brought to
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let us now look at magnetic fields due
to a current calving solenoid before
that let us see what is a solenoid Sola
no it is nothing but a coil which is
wound into a tightly packed ellipse what
is a tightly packed Alex it is nothing
max but something in this pattern
suppose if if you have a coil which is
wound very tightly in this pattern so
this pattern is known as a helical
pattern like this so this is called an
helical pattern so if you have any coin
which is in this pattern it is known as
a solenoid so now we will see what kind
of magnetic field is reduced with a
current-carrying solenoid of this form
so let us look at this now it has been
observed that with solenoid and a new
solenoid also the same experiment was
done some iodine filings were taken and
then they were placed from the solenoid
and then it was found that they arranged
themselves in a specific pattern and it
was you are surprised that it was seen
that the pattern of magnetic field lines
in case of a solenoid was similar to
that of the bar magnet you remember the
magnetic field lines pattern in case of
bar magnet they look like this length
they originated from one pole and
terminated to the other and they form
closed continuous loops so by looking at
this pattern of magnetic field it was
then told that one end of the solenoid
behaves like a magnetic north pole and
the other end of the coil annoyed
behaves like a magnetic South Pole that
means a solenoid is not a bar magnet but
the behavior of the solenoid is same
similar to bar magnet to some extent and
therefore one end of the solenoid from
where the magnetic lines are assumed to
initiate that is known as the magnetic
north pole and the other end where the
lines seem to terminate is known as the
magnetic South Pole
so here also the magnetic field outside
for
this kind of curved loops and inside if
you see the magnetic field lines are
from south to not and they are uniform
you see the magnetic field is uniform it
is in this fashion right now fit inside
the solenoid field is uniform inside the
solenoid this is a very important
property which has been put into various
useful applications right so here we saw
the pattern of the magnetic field right
and as far as direction of magnetic
field lines is concerned that is simple
in T as the direction here you will be
the field lines originating from north
poles terminating in south pole as far
as it is concerned outside the solenoid
and inside the solenoid the magnetic
field is uniform and it is directed from
South Pole do not for now let us see
where do we actually use these solenoids
what are their applications
well they are one of the most important
applications are in electromagnets
what are electromagnets they are
specific kinds of magnets which are
extremely useful for practical purposes
like in case of electric motors or
electric generators we often use these
kinds of electromagnets so solenoids are
actually used in electromagnets
how a strong magnetic field as I
mentioned in the last slide that the
magnetic field inside the solenoid is
uniform and it is strong so the strong
magnetic field produced inside solenoid
is used to magnetize magnetic material
like soft iron when placed inside the
coil for example you have this material
soft iron okay you put this material
inside the solenoid so since inside the
solenoid you have a very strong magnetic
field
therefore this material gets magnetized
so that means the magnetization of this
material increases and such materials
are then known as electromagnets
electromagnets are those magnets which
have very high van
ization right so that they behave as
even stronger magnets let's so in so in
order to make electromagnets we make use
of solenoid here you can see from this
diagram that this is a solenoid inside
the solenoid you have placed the soft
iron and then you have connected it
through a circuit now as current passes
through the solenoid magnetic field is
produced in the solenoid and magnetic
field inside the solenoid is uniform and
strong so this magnetic field magnetizes
this material right it is also you found
to be useful in transformer creation you
all are aware of the name transformer
maybe you are not aware how a
transformer actually functions but you
would know what is a transformer right
most of you would have seen transformers
outside your house is near the electric
poles and odd from there the electricity
comes to your houses
so these transformers also make use of
solenoids here if you see they have got
these solenoids with the help of which
actually the transformation of the
current and voltage takes place
now how this transformer works that we
will discuss ins in a later classes so
for now you should just know that
solenoids are useful in these
transformers also thank you please visit
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