Electric Current and its Effects Chapter – 14 Electric Current and its Effects

1 Symbols Of Electric Components In the symbol of the electric cell, the longer line represents the positive terminal and the thicker, shorter line represents the negative terminal. The wires used to connect the various components in a circuit are represented by lines. Combination of two or more cells is called a Battery. 4. Switch is used to close and open a circuit.

2 Heating Effect Of Current. 1. The wire gets hot when an electric current passes through it . This is the heating effect of electric current. In a bulb there is a thin wire called filament made up of tungsten. When current passes through it, it glows and gets heated up. In a heater there is a coil of wire called element which made up of nichrome. When current passes through element it become red hot and give out heat. 4. Electric Fuse – A Safety device in domestic circuit used to prevent electrical fire due to short circuit or overloading.

3 Magnetic Effect Of Electric Current When electric current passes through a wire it behaves like a magnet. This is the magnetic effect of electric current. 2. HANS CHRISTIAN OERSTED for the first time observed that a magnetic compass kept close to a wire carrying current showed deflection.

4 Electromagnet A current carrying coil of wire wrapped around a piece of iron is called electromagnet. It is a temporary magnet. Its strength depends on – (a) Current flowing the coil of wire (b) Number of turns of wire. Uses of Electromagnet – (a) It is used in cranes to lift heavy iron objects (b) Used to separate magnetic material from junk (c) Electric Bell – It uses an Electromagnet.

5 Electric Bell 1.Electric Bell consists of a coil of wire wound on an iron piece. The coil in electric bell acts as an electromagnet . 3. The hammer at the end of the strip strikes the gong of the bell to produce a sound. 4. When the electromagnet pulls the iron strip, it also breaks the circuit. The current through the coil stop flowing.

Made by Kartikey Thakur Class - 7th A Roll no. - 715