Page 134 - Science Class 07

Terminal : Used to connect devices with the help of conductors

Ammeter : Device used to measure the amount of electricity passing through an
electric circuit
Voltmeter : Device used to measure potential difference
Galvanometer : Device used to detect the flow of electric current

Fuse : A piece of metal wire having very low melting point

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i A charged body has either excess or deficit of electrons.
i Electrons move through a conductor from one place to another when there is a potential
difference between the two poles.
i An electric circuit through which electric current can flow is called a closed circuit.

i An electric circuit through which electric current cannot flow is called an open circuit.
I In an electric fan, the electromagnetic induction keeps the motor rotating on and makes the
blade of the fan to rotate.
I Electric energy can be converted into heat energy.
i The filament of an electric bulb is made up of tungsten.

i A fuse is attached with the electric circuit to avoid any kind of damage caused due to short
circuit.
i Electromagnets are used in various electrical equipments like generator, motor mixer
grinder, washing machine, etc.

Exercise
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A. Tick (3) the correct op on.
1. ______________ is the device which gives resistance to electric flow.
(a) Ba ery (b) Resistor
(c) Ammeter (d) Voltmeter
2. Which device is used to measure the amount of electric current passing through an
electric circuit?
(a) Ammeter (b) Voltmeter
(c) Galvanometer (d) Terminal

3. Filament of an electric bulb is made of metal having ______________ mel ng point.
(a) high (b) low
(c) very low (d) none of these

4. The piece of wire used in fuse has ______________ mel ng point.
(a) very high (b) high
(c) very low (d) low

134 Science-7