How long will a rotating magnet generate electricity?

[physior]

hello!

If I rotate a metallic cylinder that is a permanent magnet, it will generate electricity in a wire next to it?

for how long it will generate electricity? forever? or it phases out as the magnetic energy transforms to electricity? how long it will last approximately?

thanks

 

[russ_watters]

The magnet can't just be a cylinder, it needs to be polarized. Individual magnets arranged in a circle would do it. You are roughly trying to describe a generator.

And it will continue to generate electricity until you stop rotating it or its parts wear out. In the real world, that takes several decades.

 

[physior]

thanks
why it can't be a cylinder?
I can only use a cylinder or a tube! isn't there a way to be it magnetic?
also, can I make it magnetic? will it still take decades to phase out? it will give electricity for decades? what amount of electricity?

 

[CWatters]

for how long it will generate electricity? forever? or it phases out as the magnetic energy transforms to electricity?

A magnet is not a source or store of energy.

Ultimately the energy produced comes from whatever is spinning the magnet. The energy does not come from the magnet so it doesn't "wear out" the magnet.

 

[physior]

how is not magnet a store of energy? it has the potential to produce work by moving a magnetic item!

 

[russ_watters]

thanks
why it can't be a cylinder?
I can only use a cylinder or a tube! isn't there a way to be it magnetic?
also, can I make it magnetic? will it still take decades to phase out? it will give electricity for decades? what amount of electricity?

So this is for an assignment? Without knowing the details of the assignment, I'd just be guessing about what you should do.

 

[russ_watters]

how is not magnet a store of energy? it has the potential to produce work by moving a magnetic item!

That work is symmetrical/conserved. And more to the point, the magnetic field isn't consumed when doing the work. Picture it like a mass bouncing on a spring.

 

[berkeman]

hello!

If I rotate a metallic cylinder that is a permanent magnet, it will generate electricity in a wire next to it?

for how long it will generate electricity? forever? or it phases out as the magnetic energy transforms to electricity? how long it will last approximately?

thanks

Here is some introductory reading that should help you understand how magnet-based generators work:

http://en.wikipedia.org/wiki/Electric_generator

:-)