dlp@akgua.UUCP (D.L. Philen [Dan]) (10/29/84)
4
OK Folks, answers you have always wanted to know:
1. Color of lights. Fog (yellow) lights work better in
fog because of Rayleigh scattering. Scattering goes as one
divided by the fourth power of the wavelength. Thus blue
light (0.4 um) has 5 times the scattering as yellow (.6
um). Thus even though yellow lights have less total light
output (in watts) they have better visibility because of the
much lower scattering. White light is predominately blue.
Mounting the lights low on the car simply keeps the driver
from looking directly down the light path, that is, lowering
backscattered light onto the driver even more. Enought of
that! Fog lights work, end of discussion!
2. Batteries on concrete. Batteries are not recommended
to be stored on concrete because concrete is usually
saturaed with water. At least in the garage or basement
where the concrete is sitting on ground. There is enough
moisture from the battery in the casing of the battery such
that if you store the battery on the concrete a very slow
leakage current will flow to ground thus discharging the
battery. Since batteries are supposed to be stored fully
charged, this defeats the purpose. If by chance you doubt
that concrete is a good conductor of electricity, take your
shoes off go into the garage a stick your finger in the
light socket. I have even noticed a good tingle when lying
on my back under a car in the garage and grabbing the metal
housing of the trouble light. If you must store the battery
on concrete, simply place the battery on a couple of 2X4s
and you will be o.k.
Helpful hints from Dan's English Car Garage akgua!dlp