Naked Science Forum
General Science => General Science => Topic started by: neilep on 04/03/2007 22:57:20
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Dear Magnet Experts !
I'm not too sure how to word this...but....say you have a magnet ...is it always putting out pulling stuff ?...even when it has nothing near to attract ?...or does magnet joy only come into effect when a magnetizable thing comes within the magnets grasp !! ?
...also....how fast is the invisible stuff between the magnet and magnetizeable thing moving ?...do you know what I mean ? surely something is being pulled towards the magnet from the magnetizable thing...haw fast does it move ?
I am sure you appreciate the eloquence utilized in my prevailing upon you my respectful request upon thee to demonstrate your generosity of spirit to furnish me with an understanding of said magnetic joy.
Thank You
Magnet Enquirer
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Dear Magnet Experts !
I'm not too sure how to word this...but....say you have a magnet ...is it always putting out pulling stuff ?...even when it has nothing near to attract ?...or does magnet joy only come into effect when a magnetizable thing comes within the magnets grasp !! ?
...also....how fast is the invisible stuff between the magnet and magnetizeable thing moving ?...do you know what I mean ? surely something is being pulled towards the magnet from the magnetizable thing...haw fast does it move ?
Do you mean which is the magnetic force's speed? It's c (light's speed).
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Dear Magnet Experts !
I'm not too sure how to word this...but....say you have a magnet ...is it always putting out pulling stuff ?...even when it has nothing near to attract ?...or does magnet joy only come into effect when a magnetizable thing comes within the magnets grasp !! ?
...also....how fast is the invisible stuff between the magnet and magnetizeable thing moving ?...do you know what I mean ? surely something is being pulled towards the magnet from the magnetizable thing...haw fast does it move ?
Do you mean which is the magnetic force's speed? It's c (light's speed).
YES YES YES !!!..THANK YOU THANK YOU !!
I was really upset that this was not answered...is it c ?...wooo..that's fast !!
Thanks again Alberto !
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However, magnetic force is a complicated subject. When your magnet approaches a piece of iron, the magnetic field (which propagates at light's speed) begin to act on the iron atoms making them rotate a little, as a compass needle moves with the earth's magnetic field.
This process, called magnetization, is not as fast, you have to wait some more fractions of seconds to have your complete magnetic force.
Anyway, if you (ideally) had an electromagnet able to produce a perfectly collimated magnetic field, you could attract iron pieces on the moon in 1.28 seconds after switching on your device.
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That electromagnet would have an inductance so you could only change the current through it at a finite rate; how do you define the time from "switched off" to "switched on"?
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That electromagnet would have an inductance so you could only change the current through it at a finite rate; how do you define the time from "switched off" to "switched on"?
The magnetic field starts propagating exactly the instant you switch on the power for the first time. After you have switched off the power, the current keep circulating for some times, as you say. You wait until the current stops completely and then you switch on the device again.
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I would guess that the magnetic force is independant of the prescence of things to attract. As shown in some experiments, the field always takes a certian shape of attraction, which would not be the case if it was dependant on anything.
another thing about magnitism that amazes me is that you could have a magnet the size of a quarter, put it an inch above the ground, and you could pick up a paper clip. compare the sizes of the quarter vs the Earth, and you will see that A magnetic field is exponentially stronger than a gravity field.
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grear information
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grear information
Yes, grear indeed.
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The magnetic field starts propagating exactly the instant you switch on the power for the first time.
The magnetic field is proportional to the current, and the rate of current growth is limited by the inductance:
di/dt = V/L in the absence of any resistance,
or in a real solenoid with resistance:
i = V/R(1-e-tR/L)
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The magnetic field starts propagating exactly the instant you switch on the power for the first time.
The magnetic field is proportional to the current, and the rate of current growth is limited by the inductance:
di/dt = V/L in the absence of any resistance,
or in a real solenoid with resistance:
i = V/R(1-e-tR/L)
Isn't there a computer that would do this independently? Or am I missing something.
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grear information
I'm Curious!
🤔
Why do New Users join the Forum, then dig into a Specific past OP, & then Comment on it, and finally Disappear never to return?
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Yes indeed, Zero, I have noticed this phenomenon too but I have no explanation. I too have a question, more troubling imho: how can a thread go on and on when clear precise answers have been graciously provided but seemingly to no avail? Without any finger pointing these threads concern the behaviour of electromagnetic waves.