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GR9677 #91
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Problem
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This problem is still being typed. |
Thermodynamics }Second Law
The Second Law of thermodynamics has to do with entropy; that entropy can never decrease in the universe. One form of it states that from hot to cold things flow. A cooler body can thus never heat a hotter body. Since the oven is at a much lower temperature than the wanted sample temperature, the oven can only heat the sample to a maximum of 600K without violating the Second Law.
(This solution is due to David Latchman.)
(Also, since the exam is presumably written by theorists, one can narrow down the choices to either (D) or (E), since the typical theorist's stereotype of experimenters usually involves experimenters attempting to violate existing laws of physics---usually due to naivity.)
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Alternate Solutions |
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Comments |
shak
2010-08-20 17:19:23 | good trap:))) |  | ramparts
2009-10-01 17:17:54 | That's naïveté. |  | medellin
2008-10-24 17:34:29 | Why I can hot a piece of paper with a lens? You could tell me because the sun is hotter, but you cannot imagine an experiment focusing many photons of the oven so as to increase the temperature of the sample??
nobel
2008-11-04 08:41:03 |
not sure but the temperature will not increase, the heat will.
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nobel
2008-11-04 08:42:05 |
when u talk of a cooler body, we are referring to its temperature, not how much heat it has
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| | t-k-n-o
2008-06-20 19:04:16 | just consider to put the sample into de oven, its temperatue will get to 600K, but never go over 600K.!!!
evanb
2008-07-02 14:55:19 |
They're trying to lure you into computing how much power is emitted by the oven, then focus the light into a smaller area, so you have a larger power flux, then absorb that power into the sample.
Of course, we're to smart for that trap!
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evanb
2008-07-02 14:55:47 |
"too smart", not "to smart"
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| | Richard
2007-10-08 17:10:44 | I like the second solution! | |
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