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PUMPA - SMART LEARNING
எங்கள் ஆசிரியர்களுடன் 1-ஆன்-1 ஆலோசனை நேரத்தைப் பெறுங்கள். டாப்பர் ஆவதற்கு நாங்கள் பயிற்சி அளிப்போம்
Book Free DemoMagnetic effect can be made with the help of electric current.
Electromagnet:
This experiment requires an iron nail, an insulated wire, few pins, a cell, and a switch.
Experimental set-up
- Take an iron nail of \(6\)\(–10\) \(cm\) long and a flexible plastic wire (or any insulated wire) of length \(75\ cm\) long.
- Wound the wire tightly around the iron nail like a coil.
- Now, connect the ends of the wire to the cell through a switch and place the pins near the end of the nail.
- When the current is switched on, the pins clung to the tip of the nail.
- But when the current is turned off, the pins do not stick to the tip of the nail.
Important!
Do not pass the current for a long time because the electromagnet weakens the cell if it is left connected.
Inference:
When the current flows through the circuit, the coil behaves like a magnet. Whereas the coil loses its magnetism when the current is turned off. This type of coil is known as electromagnets. It is a type in which magnetic field is produced by an electric current.
Example:
![shutterstock_144120397.jpg](https://resources.cdn.yaclass.in/f68d9e9d-6191-4231-ace9-f8aa0b92f7b3/shutterstock144120397w200.jpg)
Loudspeaker
![shutterstock_527190454.jpg](https://resources.cdn.yaclass.in/d496c1b5-c8a5-4c41-833b-7209877516b1/shutterstock527190454w300.jpg)
Electric motor
![shutterstock_394408603.jpg](https://resources.cdn.yaclass.in/5f24ffb0-6321-4d46-86b3-0803a615c74e/shutterstock394408603w300.jpg)
Induction plate
Uses of electromagnets:
1. Electromagnets are so strong that it is used to lift heavy loads. In a junkyard, a crane attached to an electromagnet is used to carry heavy metal loads. It also helps to separate magnetic materials from the junk.
![shutterstock_1040746411.jpg](https://resources.cdn.yaclass.in/9db4b61a-2bba-49f8-93d8-0aea4a1e855b/shutterstock_1040746411-w300.jpg)
Junkyard crane
2. Tiny electromagnets are used by the doctors to remove small pieces of magnets from the eye.
![shutterstock_262898927.jpg](https://resources.cdn.yaclass.in/b253ab55-b8b4-4aa2-b185-8ab4ef0399cd/shutterstock_262898927-w300.jpg)
Electromagnets used in the eye surgery
3. Even children playing with the toys and dolls have electromagnets in it.
![shutterstock_1457615303.jpg](https://resources.cdn.yaclass.in/809d283c-fd77-43b8-ba28-49f44c1fc13f/shutterstock1457615303w200.jpg)
Magnetic toys
Electric bell:
A good example of an electromagnet is an electric bell. It consists of a coil of wire, an iron piece, a hammer, and a contact screw.
![shutterstock_1723586860_new.jpg](https://resources.cdn.yaclass.in/f4a2d69c-62b9-43b8-92e9-93d6ef66c1de/shutterstock_1723586860_new-w300.jpg)
Working:
- The iron piece is wounded with a coil of wire, which acts as an electromagnet.
- The hammer at the end of an iron strip is placed near an electromagnet.
- A contact screw is placed near the iron strip so that when it is in contact with the screw, current flows through it.
- Thus, the coil becomes an electromagnet and pulls the iron strip.
- When the iron strip is pulled, the hammer at the end of the strip strikes the gong of the bell, and sound is produced.
- The circuit breaks, and the current flow is stopped when the electromagnet (coil) pulls the iron strip.
- In this case, the coil is no longer an electromagnet, and hence, it does not attract the iron strip.
- Again, the iron strip touches the contact screw when it reaches its original position. This completes the circuit of the electric bell.
- Once again, the hammer strikes the gong when the current flows in the coil.
- Every time when the circuit is completed, the hammer strikes the gong.
- This process is repeated again and again and makes the bell ring.