2007-02-17 17:29:41 · 8 answers · asked by fred 1 in Science & Mathematics ➔ Physics
You are right, light is a form of energy (notice the indefinite article, “a”)…there are other forms which the light can be transformed into.
The light is bouncing around the room very quickly (at the speed of light). It collides with the walls and other objects in the room many, many times as it bounces back and forth. During each collision the light looses some of its energy. The light energy is slowly absorbed into the objects in the room as heat energy. Since the light travels so fast and participates in a very large number of ‘bounces’ in such a short period of time, the absorption process is very fast….almost instantaneous to our eyes. The total energy is always conserved, but just not the form.
Light is an electromagnetic wave.
The light we see in a room is just a tiny fraction of the total amount of electromagnetic radiation present. The visible spectrum is only from about 400 nm to about 700 nm, outside of this tiny range we cannot “see” it, so it does not look like it is there to the naked eye.
Some of the light energy which is absorbed into heat is radiated back outward (the walls act as a sort of ‘black body radiator’ in a way). The walls absorb the light, heat up, and then radiate light away; they radiate light similar to the effect of a red-hot piece of metal. But unlike the metal, which radiates heat in the visible spectrum due to its extreme temperature, the walls are much cooler and thus emit light of much less energy per photon (lower frequency, higher wavelength). The walls emit radiation which has considerably longer wavelengths…light that we cannot see but is never-the-less there.
So the total energy in the room is indeed conserved, but it just changes form. The light gets absorbed into heat and some of it is transformed into a lower frequency form of light.
2007-02-17 17:43:55 · answer #1 · answered by mrjeffy321 7 · 0⤊ 0⤋
The problem comes from incomplete understanding of the law of conservation of mass and energy, Energy can neither be made nor destroyed, but can only be converted from one form to another, including mass. Light in the room was coming from the bulb by the electricity which was running into it. So, when you switch it off, the electricity remains and goes some where else. And if that electricity is switched off, the fuel is conserved.
We are talking of the conservation of energy in a closed system and no system is really closed except the universe as a whole.
2007-02-17 17:42:19 · answer #2 · answered by Swamy 7 · 0⤊ 0⤋
Energy is conserved that is true but it is not like that the light energy will remain in form of light energy. It can be converted to ome other form. Light consists of waves and these waves travel forward. Just as when you speak your sound waves travel forward and don't remain near you forever. These waves are propagated through the medium and lastly get converted to some other form of energy
2007-02-17 17:38:23 · answer #3 · answered by Tariq M 3 · 0⤊ 0⤋
Light is a form of energy in action. Therefore it is not being conserved. So when a Goth switch is turned off the source of energy is gone.
2007-02-17 17:36:02 · answer #4 · answered by kelli s 1 · 0⤊ 0⤋
I assume you're trying to say "why does the light not stay around when you switch the electric off" ... n'est pas ?
Because, the switch cuts off the electricity to a light bulb which is vacuum filled and operates by the electricity causing a filament to become incandescent. With the power off, the filament goes cold and gives off no light ... Bingo! the light goes away.
2007-02-17 17:44:18 · answer #5 · answered by Norrie 7 · 0⤊ 0⤋
It actually *does* remain in the room. It is absorbed by all of the things in the room. Since there are no perfect reflectors, each time light reflects off of something, some small fraction of it is lost (to heat) in the material it reflected from.
HTH ☺
Doug
2007-02-17 18:08:47 · answer #6 · answered by doug_donaghue 7 · 0⤊ 0⤋
I do guard capability anyplace i can... this international warming stuff concerns me... yet i wish that I BEAM like a mild domicile... sending a skinny remarkable beam out into the darkness, guiding domicile the stranger, signalling to the misplaced helping out anyplace i can... i do no longer could even know that i've got helped, or how i've got helped, that is none of my business enterprise... yet I do it besides, only in case! after all... sometime, i'd prefer somebody elses remarkable shining mild, guiding me domicile!
2016-11-23 16:10:20 · answer #7 · answered by pirozzi 4 · 0⤊ 0⤋
light have also particle nature n by this energy is conserved.
and scattering of light is it's property.
2007-02-17 18:05:57 · answer #8 · answered by Anonymous · 0⤊ 1⤋