On 12/20/2010 12:35 AM, gdaught6@stanford.edu wrote:
> Mike wrote...
>
>> Conservation of energy in the universe - materials absorb and radiate
>> energy at the same rate.
> No they don't. An object in thermal equilibrium with its surroundings will
> absorb
> and radiate energy at the same rate.
>
> If it absorbs more than it radiates, it will heat up. If it radiates more
> than it absorbs, it
> will cool down.
An object can not radiate more energy than it receives. I can radiate
more than it is receiving at a given time IF it has already received an
excess. IOW if you have been pumping a given amount of *radiant* energy
into an object and it reaches thermal equilibrium it will be radiating
as much as it receives. Now if you reduce the radiant energy input the
object will contain more energy than it is receiving and will radiate
that excess until it again reaches thermal equilibrium. However it
will never radiate more energy than it *has received*.
If you are pumping energy into an object via any normal means it still
can not radiate more than the total energy input. The only time it can
radiate more than the energy being input is when the input is reduced
and then only until equilibrium is reached. That's neglecting the point
if you are able to input enough to create fusion, I think that is still
running a deficit.
That's about the best I can explain it.
73
Roger (K8RI)
> Then, consider an incandescent filament... if you 'pump' energy into it (e.g.
> !^2 R
> heating) it will heat up until it is radiating as much as the energy being
> supplied. Of
> course some of the (heat) energy will be conducted away, as well, not just
> radiated,
> and if the filament is in a tube, emitting electrons, the electrons will
> carry away some
> of the energy in the form of their kinetic energy, if the temperature is high
> enough
> that the electron's kinetic energy exceeds the metal's 'work function.'
>
> Things are always so complicated. My simplification is:
>
> Use a BIG blower, blow LOTS of air, and put headphones on so the fan noise
> doesn't
> bother you! [You can paint the 'phones black if you like!]
>
> 73,
>
> George T Daughters, K6GT
> CU in the California QSO Party (CQP)
> October 1-2, 2011
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|