# Calculating current
**URL:** https://boards.straightdope.com/t/calculating-current/812725
**Category:** Factual Questions
**Created:** [April 19, 2018, 6:32pm UTC](https://boards.straightdope.com/t/calculating-current/812725 "2018-04-19T18:32:57Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)
#### Post date: [April 19, 2018, 6:32pm UTC](https://boards.straightdope.com/t/calculating-current/812725/1 "2018-04-19T18:32:57Z")
I have a magnet of known strength in gauss and a certain distance r from a conductor and spin the magnet in a circle around the conductor. What determines how much current will pass through the conductor? Speed of the magnet? Size and shape of the conductor? Conductivity?
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [April 19, 2018, 6:42pm UTC](https://boards.straightdope.com/t/calculating-current/812725/2 "2018-04-19T18:42:16Z")
[Faraday’s Law of Induction.](https://simple.wikipedia.org/wiki/Faraday%27s_law_of_induction)
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### Author:  [@Ignotus](https://boards.straightdope.com/u/Ignotus)
#### Post date: [April 19, 2018, 8:36pm UTC](https://boards.straightdope.com/t/calculating-current/812725/3 "2018-04-19T20:36:41Z")
> [@beowulff](#):
>
> [Faraday’s Law of Induction.](https://simple.wikipedia.org/wiki/Faraday%27s_law_of_induction)
Yeah, but that double integral already is bound to scare people away from further study of physics…🙂
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### Author:  [@Ignotus](https://boards.straightdope.com/u/Ignotus)
#### Post date: [April 19, 2018, 9:30pm UTC](https://boards.straightdope.com/t/calculating-current/812725/4 "2018-04-19T21:30:01Z")
If you’re not much into multidimensional calculus, [Örsted’s rules](https://en.wikipedia.org/wiki/Oersted%27s_law#%C3%98rsted's_rules)might seem simpler to apply. Keep in mind that they are bidirectional; i.e. a current in _this_ direction is neither a cause nor a follow from a magnetic field in\* that\* direction. They simply tend to keep up!
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### Author:  [@naita](https://boards.straightdope.com/u/naita)
#### Post date: [April 20, 2018, 2:21pm UTC](https://boards.straightdope.com/t/calculating-current/812725/5 "2018-04-20T14:21:40Z")
> [@Saint\_Cad](#):
>
> I have a magnet of known strength in gauss and a certain distance r from a conductor and spin the magnet in a circle around the conductor. What determines how much current will pass through the conductor? Speed of the magnet? Size and shape of the conductor? Conductivity?
Induction creates an electromotive force, a voltage. The size, shape and conductivity of the conductor are therefore all factors in how much current will flow.
The electromotive force depends on how the magnetic field changes and/or the speed of the electrons in the conductor relative to the magnetic field. So the speed of the magnet matters.
What do you mean by spinning the magnet in a circle around the conductor? Is it moving around the conductor like the Moon around the Earth with the conductor as the axis of the orbit? That’s not going to create much induction.