for a long period of time electricity
and magnetism were thought to be
unrelated phenomena until
electromagnetism was discovered by a
Danish scientist named Hans Christian
ørsted
once a piece of wire with electric
current flowing through it was placed
next to a compass but the needle of the
compass didn't move until the wire was
held near to the compass again but in a
different direction from this accidental
discovery we found that electricity and
magnetism are from the same fundamental
forces called
electromagnetism every electric current
which passes through a conductor creates
a magnetic field around it this happens
to huge high-voltage power lines that
carry electricity across great distances
to tiny traces of a motherboard this
means electromagnet is a type of a
magnet in which the magnetic field is
produced by current now if we take a
piece of wire and apply a potential
difference to its sense
electric current will pass through it
and this will cause a magnetic field
around the wire the biggest advantage of
an electromagnet is the polarities can
be changed by reversing the flow of
current
it also requires some convention to find
the polarity of electromagnets
we use the right hand rule to do that
the field is oriented according to the
right-hand rule if you grab a wire like
this the thumb shows the duration of the
current flow and the other four fingers
show the direction of magnetic field so
now you can just use the wire as an
electromagnet but as a weak one if you
make a loop of wire with electric
current passing through it the current
carrying loop of wire will pass through
the center of the loop concentrating the
magnetic field there as you get further
away from the loop the magnetic field
quickly weakens and inside of the loop
you get a nice strong magnetic field now
if we make another loop from the end of
the first loop in a presence of two
loops the magnetic field will align with
each other making the overall magnetic
field much stronger this means you can
just add loops one after another to make
the magnetic field much stronger so now
you can say the conventional way to
increase the magnetic field is to loop a
bigger length of wire over and over
again that way you will end up making a
coil which is actually an electromagnet
like other magnets this also have a
North Pole and a South Pole now if we
put a ferromagnetic iron bar inside of
the coil the iron bar will be pulled at
the center because the concentrated
magnetic field is at the center of the
coil and the
we'll stuck there until you release the
voltage to make a nice strong
electromagnet you have to wrap a long
piece of insulated copper wire to a
magnetic core iron is great for this it
is just that if you do have a magnetic
core the strength of the magnetic field
is much higher ferromagnetic materials
have many smaller individual magnetic
domains these domains are actually tiny
little magnets and each one of them has
its own magnetic field normally these
domains are aligned randomly and they
cancel each other out
however in a presence of an external
magnetic field these domains align with
each other so the ferromagnetic iron bar
becomes magnetized the magnetized iron
bar and the external magnetic field
align with each other making the overall
magnetic field much stronger so a core
of a ferromagnetic material like iron
serves to increase the magnetic field
which is created by the loops of
insulated copper wire now you may ask
why most of the time insulated copper
wires are used for electromagnets well
copper is used because it has a low
electrical resistance this means it is
easy for the current to flow through it
also a copper wire can easily be shaped
to make a coil and because of the thin
layer of insulation it saves some space
so you can wind more wire in a limited
space you can just make yourself an
electromagnet by just winding a long
piece of insulated copper wire to a nail
or something like that and you have to
keep in your mind that the generated
strength of a magnetic field is
proportional to the amount of current
passing through the windings so by
changing the current passing through the
coil changing the number of windings
changing the clothes lengths changing
the length and diameter of the wire you
can change the electromagnetic strength
so that was the basis of an
electromagnet please like share and
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