Rowlett defines foot-candle as such:
It is an obsolete unit of illuminance and has been replaced by the
lux. Thus this product should be rated in lux, as it appears to be in
parenthesis. You must contact this person and have him remove at once the
obsolete term foot-candle from his literature and stick completely with the unit
lux. I would think there is an error here as 2000 lux seems like a real
bright light for a dental device. What is this device used for?
Recently I had some of my old silver amalgam filings replaced with epoxy
type. They used some type of science fiction looking type laser gun that
emits a purple light for speeding up the hardening. Is this what this
product is suppose to do? Or is this the bright light used to see into the
mouth?
The unit watts per square centimetre is incorrect as it is stated and
should be expressed as watts per square m (W/m^2). It is not proper SI to
used prefixed units (other then the kilogram) in the denominator of a fractional
_expression_.
In reference to the use of watts per square metre it would appear to be a
measure of how much light energy is striking a one square metre surface each
second. I don't know much about light science. But I know
that the units they are using are wrong and need to be corrected.
Personally, a product that can't use correct units or unit conventions is a
product to avoid. The use of old and obsolete units speaks clearly that
the device is the product of obsolete thinking and is of no use in the 21-st
century.
Euric
----- Original Message -----
From: "mavi fibe" <[EMAIL PROTECTED]>
To: "U.S. Metric Association" <[EMAIL PROTECTED]>
Sent: Monday, 2004-05-31 11:14
Subject: [USMA:30023] Microlux
> this last week and she ran into the following pamphlet
> from the above-referenced company - or is it a product
> name?... (my personal "comments" - except for the Lux
> one - are in parenthesis):
>
> Question 1: What is the output for the Microlux?
> Answer: 200 Foot Candles (SIC) (over 2000 Lux)
>
> Question 2: Why is this measured in foot candles
> instead of the way we would measure curing lights in
> mW/cm2?
> Answer: Photometric measurement (foot candles) is the
> way visible light is measured because that is the way
> the human eye sees light (?? I beg your pardon???...).
> Curing lights are measured in radiometric units
> (mW/cm2) and cannot (???) be compared to photometric
> measurements.
>
> I need help here to understand this issue better. Can
> anyone comment on this piece above please? It sounds
> to me that this guy's understanding of Physics is
> dismal to say the least, but since luminescence
> science is not my forte...
>
> And, finally, if someone can write these guys to
> "straighten them out" I'd really appreciate it... I'd
> be willing to do it myself also if I could technically
> dispute their writings...
>
> Thanks for your help.
>
> Marcus
>
> =====
> Jesus ONLY settles for THE best, so
> what excuse can you possibly give to NOT go SI???
>
> ______________________________________________________________________
> Post your free ad now! http://personals.yahoo.ca
>
>
