Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
On Jan 24, 2007, at 3:31 PM, Bernard Cleyet wrote:
> I doubt a $10 IR thermometer. is that sophisticated *, even in this
> 21st. cent. They likely make use of the T^4 relation,
What is proportional to T^4 is the total intercepted intensity. But
that intensity is also proportional to 1/r^2, where r is the distance
from the source. Therefore, the reading, for a given T, would change
with r. Does the indicated T change when r is changed?
The only things that do not change with r are the location of the
maximum and ratios of partial intensities at two different wavelengths.
My guess is that T is determined from a ratio of two partial
intensities. Some kind of a filter, and two detectors, would make this
possible, at least in principle.
_______________________________________________________
Ludwik Kowalski