Electromagnetic Induction

Today i wanna go back to where we've left our previous discussion on electromagnet . The last sub-topic we've discussed was about d.c motor principle.

The next discussion will be subtopic 3.3 which is one of my favorate.. its about electromagnetic induction. I like this one bcoz its like doing an illusion .Just imagine without a battery or solar power supply can we still light up a bulb?..

Usually to light up the bulb we need continuous supply of current, which we get it from batteries or solar energy. But in this topic, we dont need those batteries..all we need is a magnet.


YEah..magnet alone can produce current..but HOW??
This process is what we call magnetic induction..
By bringing the magnet closer or moving it into the coils of wire, u can produce current which is known as Induced Current...Meanwhile, the emf produced is known as induced emf.
U can actually ligt up your torchlight without any batteries....watch this


So in SPM, u must be able to
i. describe electromagentic induction... HOW??

When we move a magnet into a coil of wire,there is change in magnetic field. In other wrords, the magnetic fields are being cut which cause an induced e.m.f (electromotive force) to be produced.
An induced current flows through the wire and this phenomenon is called electromagnetic induction

To understand this better..u can watch these videos..

look!.. what happen to the ammeter reading when a magnet is brought close to the coil..




u can also download this note to get a clearer picture on electromagnetic induction.
The same concept is applied in bicycle's dynamo . The bulb lights up when u start to cycle..no batteries are needed..all u need is to continue cycling.
This is the mysterious world of magnet..it generates current when the magnetic fields being cut.
I'll discuss more about this on next post.