LEARNATHON
III

Competition for grade 6 to 10 students! Learn, solve tests and earn prizes!

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Theory:

You're given a long iron nail, copper wire with insulation, and a battery. Is it possible to make your own electromagnet?
 
Yes, it is possible to create your own electromagnet. Let us discuss the following activity to learn how to make an electromagnet.
 
An electromagnet is relatively simple to construct. Wrap some insulated copper wire around an iron core, and you're done. When you connect the wire to a battery, an electric current flows and the iron core becomes magnetised. The iron core loses its magnetism when the battery is disconnected. If you want to make an electromagnet, follow these steps.
 
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Simple electromagnet
 
Wrap the wire around the nail neatly. The stronger your electromagnet is, the more wire you wrap around the nail. Make sure that enough of the wire is left unwound so that you can connect the battery.
 
When wrapping the wire around the nail, make sure it's all going in the same direction. This is necessary because the direction of a magnetic field is determined by the electric current that generates it.
 
The flow of electric charges creates a magnetic field. For example, the magnetic field around a wire with electricity flowing through it would appear as a series of circles around the wire if you could see it.
 
If the current is moving directly towards you, the magnetic field created by it circles the wire in a counter-clockwise direction.
 
When the electric current is reversed, the magnetic field is changed and the wire is circled in a clockwise direction. If you cover some of the wire around the nail in one direction and some in the other, the magnetic fields from the two sections fight and cancel each other, reducing the strength of your magnet.
 
Fleming's Right-hand rule:
Stretch the thumb, forefinger and middle finger of your right hand mutually perpendicular to each other. The forefinger indicates the direction of the magnetic field, and the thumb indicates the direction of motion of the conductor. In that case, the middle finger will indicate the direction of the induced current. Fleming's Right-hand rule is also called the 'Generator rule'.
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Generator rule