Safety & Applications - Electricity, Science Video Lecture - Natural Science

hello kids let us understand the
applications of heating effect of the
current and also the safety measures
against its undesirable outcomes now we
know that the electric current flow
causes heating effect in this circuit if
the current and also the heat increase
due to the overloading or short-circuit
etc it may damage some part of the
circuit like the wires and even
appliances like TV fan etc this may even
lead to fire so we need to avoid this
kind of electrical hazard which can
cause great trouble and loss for us this
means when the circuit is getting too
hot leading to hazards we must stop the
electricity flow but we can't do it
ourselves every time then who does it or
who should do it in a previous class we
saw that the bulb wasn't glowing because
the circuit was broken as the filament
was burnt due to overheating so we can
take a simple idea from that if we break
the circuit the current wouldn't flow
through the broken or the open circuit
but we cannot turn all the switches off
or we cannot cut the wires quick enough
to break the circuits in time this is
because overloading or short circuit can
happen in a split second and thus we
won't get enough time to act
hey what if a small part of circuit gets
damaged automatically just like the
filament in the burl and breaks the
circuit this way the flow of excessive
current shall be automatically stopped
as the circuit would be broken and thus
the damage to the circuit and its
element can be prevented
it can be a small piece of wire which
can be a part of the circuit and we can
replace it
once it gets burnt saving other parts of
the circuits regarded so we shall insert
a small piece of wire in the circuit
this wire is weaker that is its
tolerance limit for the current is lower
than the other parts of the circuit
hence it gets damaged and stops the
electric flow of current before other
parts of the circuit gets damaged look
here the bulb didn't get damaged due to
the excessive current just the small
wire with less tolerance got burnt the
bulb is intact but again this method
won't be correct to implement as it
wouldn't be easy to add or replace this
wire in the circuit correct we have a
better way to implement this and
electric fuse is made for this purpose
only an electric fuse is a piece of wire
which melts and thus breaks the circuit
when the current flow is increased
suddenly saving the other parts of the
circuit and our valuable appliances this
wire is kept inside a cover made of
plastic or other non conductive
materials and is easily replaceable like
a bulb at homes or even in the other
buildings you might have seen this fuses
inserted in all the electrical circuits
you know there is a maximum limit on the
current which can safely flow through a
circuit if by accident
the current exceeds the safe limit the
wires may become overheated and may
cause fire but if a proper fuse is there
in the circuit it will blow off and
break the circuit an electric fuse is
thus a safety device which prevents
damages to the electrical circuits and
even fires but once burned the fuse
needs to be replaced with another one
it's a good solution but do we have a
better solution nowadays there is a
better solution
MCB are miniatures circuit breaker the
MCB works like an automatic switch the
MCB breaks the circuit and stops the
current flow when the circuit is
overloaded just like a fuse as we saw
the wire in an electric fuse gets burnt
while saving the circuit but the MCB is
made on a concept of an automatic switch
the MCB is like an automatic switch
which gets turned off by itself when the
current in the circuit increases
abnormally so we just need to turn on
the switch to restart the current flow
once the danger is gone we don't need to
replace it
every time like a fuse we know due to
the heating effect of the electric
current the wire gets hot when an
electric current passes through it can
we make use of this property or is it
just useless or at times even hazardous
to us let us look at some of the
appliances used at home how does the
room heater or the electric heater used
for cooking work even the iron box which
is used for ironing our clothes you know
all these appliances which are made to
produce heap like heater toaster
etc run on the heating effect of
electricity let us see how the heating
effect of electric current is used in
this appliances all these appliances
contain a coil of wire this coil of wire
is called an element for example after
the heater is switched on it
element becomes red-hot giving out heat
not all elements produce the same amount
of heat the amount of heat produced in a
wire depends on many things such as its
material length and even thickness
thus for different requirements the vias
of different materials different lengths
and thicknesses are used so we see the
heating effect of current is also useful
to us in many ways to sum up the heating
effect of current can lead to hazards
like burnt wires damaged appliances and
even fire due to overloading or
short-circuiting but it can be prevented
- most of the times various safety
devices like fuse and MC B's are used to
prevent this the heating effect of
current is not always undesirable we
make use of it in the room heaters
heaters used for cooking iron used for
ironing clothes etc that was all about
the heating effect of electric current
bye bye kids