scott wrote:
>>> I really don't see the problem.  Do you understand what happens if 
>>> you short a battery with a wire?  You will get a huge current flowing 
>>> even though the voltage across the wire is virtually zero.
>>
>> How the hell do you figure that?
> 
> Because the resistance of the wire is way lower than the internal 
> resistance of the battery.  DId you never notice that the more current 
> you draw from a battery the lower the voltage across its terminals?  If 
> you *short* a battery, the voltage is pretty much zero.

I thought the voltage of a battery only decreases if you try to draw 
current faster than the chemical processes inside the battery can 
restore it? (I.e., it's a flaw parculiar to chemical batteries.)

>> Anyway, presumably a superconducting magnet is bizare enough that 
>> Ohm's law doesn't apply. (Hmm, I = V/R where R = 0. Yeah, that looks 
>> pretty undefined to... oh, wait, you're that guy who things that 
>> division by zero is defined, aren't you?)
> 
> You don't need to do that, batteries have an internal resistance, Ri, so 
> the current flowing will simply be Vbattery / Rinternal.  With zero 
> volts across the super-conductor, but a current flowing.
> 
> Ohms law works perfectly well, the fact that R is zero simply means you 
> can have whatever current flowing you want with no potential 
> difference.  Which is exactly how superconductors work.

Heh. Superconductors truly *are* weird...

-- 
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