Contents
Electric cell
- An electric cell has two lines.
- One is shorter and the other line is longer.
- The longer line represents the positive terminal.
- The shorter line represents the negative terminal.
What is a Battery?
- Combination of two or more cells is known as the battery.
- In a battery the positive terminal of one cell is connected to the negative terminal of the other cell.
- Battery is a source of energy which converts chemical energy into electrical energy.
- They are used in remotes, electronic games, tv etc..
- The batteries used in trucks and inventors are also made from cells. They are made from many cells and are thus termed as a battery.
Electric Current
- The flow of electrons or the flow of charge is known as Electric Current.
- The SI unit of Current is Ampere (A).
- Electric Current is a scalar quantity.
Electric Circuit
- Electric Circuit is a circuit with various electrical components in which there is a flow of electric current.
- The various components of electric circuit are an electric cell, an electric bulb, connecting wires and a switch.
- The thin wire in the bulb is known as filament.
- When the switch is in on position the circuit from the positive terminal to the negative terminal is complete and is considered as a closed circuit.
- When the switch is in off position the circuit is incomplete and is said to be open.
- There is no flow of current when the circuit is open.
Heating effect of electric current
- When the electric current passes through any conductor it gets hot. This phenomenon is known as the heating effect of electric current. For example; An iron becomes hot when we switch on it.
- The amount of heat produced in any conductor depends on it’s material, length and thickness. That’s why we don’t use same conductor for various purposes.
- Some wires start melting when a large amount of electric current is passed through them. Electric fuses are made with the help of these wires.
- If the wire exceeds the given safe limit, the wires may become overheated and can cause fire.
- MCBs( Miniature circuit breakers) are used instead of fuses as it gets automatically turned off when the current exceeds the safe limit.
Magnetic Effect Of Electric Current:
- When a magnetic field is created around a conductor when electric current is flowing through it then this phenomenon is called as the Magnetic effect of electric current.
- When electric current passes through a wire it behaves like a magnet.
Electromagnets:
- An electromagnet is a magnet made up of soft core by the passage of electric current.
- They are made strong to lift up various loads.
Uses of electromagnets:
- They are used to separate magnetic material from the jink.
- Doctors use them to remove small pieces of magnetic material stuck into the eye and are also used in a MRI.
- Many toys have magnetic material inside them.
- They are used inside speakers.