Page 130 - Science Class 07
P. 130
v Terminal : It is used to connect devices v Filament : It is a form of resistance which is
with the help of conductors. It consists of a made up of a metal with high mel ng point
metal nut on a screw thread through which such as tungsten. It is used in electric
wires are connected. bulbs. When electric current passes
v Switch : It is used to connect disconnect through it, it becomes very hot and starts
the loop of electric current. glowing.
Switch
Filament
v Ammeter : It is a device which is used to
measure the amount of electricity passing EFFECTS OF ELECTRIC CURRENT
through an electric circuit. When an electric current passes through a
conductor, it gives some energy to the
conductor. We can also say that people can
make use of electric energy in various ways.
Hea ng Effect of Electric Current
When an electric current passes through a
conductor, it loses a part of whole energy. This
Ammeter
energy is converted into heat. Actually, each
v Voltmeter : It is a device which is used to and every conductor gives resistance to current
measure poten al difference. when it passes through them. The magnitude
of resistance depends upon the material used
to make the conductor.
For example, a wire made up of copper gives
less amount of resistance as compared to the
wire made up of iron. It is because copper is a
be er conductor than iron. You should also
Voltmeter remember that the more a conductor offers
v Galvanometer : It is a device which is used resistance the more heat is generated as well
to detect the flow of electric current. as the more electricity is consumed. This
applica on of electric current is, however, used
to make various devices and electrical
appliance.
Look at the given appliances in which resistance
of different magnitudes is used to obtain
Galvanometer different amount of heat or light.
130 Science-7
