Are there types of laser light, color or wavelength, whole beam can be seen in daylight conditions with a special eyeglass filter? [more inside]
posted by pallen123
on Mar 6, 2012 -
I have a candle and its brightness is exactly one candle power or candela. If I buy a 10,000 candle power torch/flashlight, does that mean it's 10,000 times brighter (and what does that mean) or that I can see it 10,000 times further away? Are these the same thing and why do they seem unbelievable?
posted by westerly
on Jun 8, 2010 -
Why does an incandescent light bulb have an broad, continuous spectra when viewed with a spectrometer? Why doesn't it have some lines like a sodium lamp?
I guess I'm asking why photons come off of a black body and why are their wavelengths spread out.
Bonus points for clarity and accessibility of the answers.
posted by bdc34
on Oct 7, 2008 -
Why do porous objects (wood, textile, hair, etc) appear darker when wet then when dry? A googling gave me this
("surface reflection and refraction"), but that doesn't sound entirely reasonable, as it merely talks of light being scattered, but the light in question is already diffuse. This
also gives some suggestions, but nothing conclusive. Any chem/physics MeFiers know this?
posted by fvw
on Dec 12, 2003 -