Electric Current

We use many electrical appliances in our home.

In hospitals, factories, Shops, offices also there are many electrical appliances.

These appliances work on the electricity provided by government company. Or on various types of

electricity provided. Both of these types of electricity is called Electric current.

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The field through which electric current flows is called electric field.

Source of electric current (either Government or electric cell) in electric field, transmission lines, electrical

appliances, and a switch to start/stop electric current.

Electric current flowing through the field generates current of charges(electron) or flow. When silk cloth and glass rod or woollen cloth and ebonite rod are rubbed electric charges are produced. But the charges remain still on those bodies. With the help of electric cell these static

charges are set in motion and electric current is generated.

Types of electric cell

1) Simple Cell> 2) Leclanche Cell> 3) Dry Cell> 4) Nickel-Cadmium

Cell

5) Button Cell

Simple Cell (Voltas Cell)Positive pole - Copper rod

Negative pole – Zinc rod

Chemical – Dilute Sulphuric acid.

Leclanche> Cell (Cannot be recharged)

Positive pole - Cylindrical Porous pot with mixture of Manganese dioxide and carbon

Negative pole - Zinc Rod

Chemical– Ammonium chloride>

Dry cell> (Cannot be recharged)

Positive pole – Carbon rod

Negative pole – Zinc can Chemical – Manganese dioxide, graphite, zinc chloride and ammonium chloride

Nickel-Cadmium Cell> - (Can be recharged)

Positive pole - Nickel

Negative pole - Cadmium

Chemical - Potassium Hydroxide>

Button Cell( Lithium Cell)Cannot be recharged

Positive pole - Carbon

Negative pole - Lithium Iron Phosphate

While electric current flows through a conductor, it behaves

like a magnet. Hence a magnetic field develops around it, which causes the

deflection of magnetic needle.

Electro-Magnetic Induction- If there is a change in the magnetic field associated with a coil of wire ,electric

current begins to flow through the coil. Such a current is called induced current. This phenomenon of the change

in a magnetic field and the electric current that it generates is called electro-magnetic induction

The working of electric motor is based on the principle of

electro magnetic induction..

When electric current is passed through a conductor, it

works like a magnet. Such magnets are called electro-magnet.

Uses of Electro-Magnet – Loudspeaker, Telephone, Electric crane.Electric bell also works on the principle electro-magnet .

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Electrical Conductors- Substances through which

electricity can flow easily are called Electrical Conductors.

Example : All metals

Electric insulators – The substances which do not carry

electric current are called Electric insulators. Example: Glass, Paper, Rubber, Plastic, stones, etc.

Electric appliances and its symbols.