Re: [Phys-l] IR thermometer buy

[Bernard Cleyet <bernardcleyet@redshift.com>]

Excellent point.   To determine I would necessarily dismantle the 
bolometer.  OR sit on my arse and use Google.   We'll see.  (FOS)

bc

Ludwik Kowalski wrote:

> 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, a retired physicist
> 5 Horizon Road, apt. 2702, Fort Lee, NJ, 07024, USA
> Also an amateur journalist at http://blake.montclair.edu/~kowalskil/cf/
>
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