now we’ll start with the topic of electromagnetic
interactions, and we’ll start with study
of some facts, about electromagnetic interactions.
which are quite useful in analyzing different
kind of, situations related to electromagnetic
forces.
a very first point.
we’ll study about is.
a static charge.
produces.
only electric field.
in its surrounding. and. only external electric
field.
can exert, a force.
on a static charge.
this is point which we already discussed in
the section of electrostatics, lets discuss
once again if we are given with a charge at
rest.
this is plus q charge and we know it produces,
an electric field in its surrounding in radially
outward direction.
say if e vector is the electric field which
produces.
and say an external electric field, e external
vector is applied.
then this external electric will interact
with the electric field of this charge, and
hence.
this charge experiences force due to the external
field.
and say if we apply a magnetic field induction
b-external vector over here.
then we can say as charge does not produce
its own magnetic induction there won’t be
any interaction of this external field magnetic
field with the.
electric field or any other field produce
by the charge.
because it can interact only with the.
magnetic field produce by any source so here
there is, no magnetic field so we can say,
that external magnetic field can never exert
a force on static charge.
second point if we discuss about a moving
charge we can write.
a fact that a moving charge produces.
both electric field, and magnetic field.
in its surrounding. and we can say that, both
electric, field.
and magnetic field.
can exert.
force.
on the moving charge.
here you can see if we are having a charge
plus q moving with a velocity v then we know
it produces e vector in its surrounding.
as well as it produces b vector in the surrounding
which is given by biosavart law we already
studied in the previous section.
and in this situation if an external electric
field e-external vector. and an external magnetic
field b-external vector is applied.
then both of these external fields can interact
with the electric and magnetic field produce
by the moving charge.
so both of these will exert a force on this
moving charge.
so we can say a moving charge produces both
field in the surrounding that’s why it experiences
a force due to both kind of external fields.
there is one more point lets continue on the
next sheet.
lets continue with the third point which is
about a current carrying wire for which we
can write that.
a current carrying wire.
produces.
only magnetic field.
in its surrounding. and only external magnetic
field.
can exert a force.
on the current carrying wire.
or we can also write current carrying.
conductor.
this because if we are given with a current
carrying wire. as net charge on the wire is
zero in its surrounding net electric field
is zero as it does not produce any electric
field because total charge on the wire is
zero.
but as, there are moving charge produces magnetic
field in its surrounding.
so when an external magnetic field b external
vector is applied.
this external magnetic field will interact
with the magnetic induction produce by the
wire. and hence due to this interaction the
wire will experience a net magnetic force
onto it.
so always remember in case of a static charge
only electric field can exert a force on it.
in case of a moving charge both electric and
magnetic fields can exert a force on it. and
in case of a current carrying wire only magnetic
field can exert a force on it electric force
will not be exerted on the wire because, net
sum of all charges on this wire is equal to
zero as it is.
electrically neutral.
