The adding of the energy of relfected light?

[Pirate88179]

I had no idea what topic this might fit in so, after looking through all of the topics for a while, I decide to use "News" as it says for things that do not fit into other topic areas.

What I am talking about here is this...

I am in a small room where one wall is covered with mirrors.  I turn on a single source light, say, a very bright 3 watt led bulb.

This bulb puts out X amount of light.  I look at the wall and see the reflection of an exact duplicate of this light bulb giving out Y amount of light.
Now, the reflection appears to be as bright as the real bulb but, that probably is impossible because I doubt my mirrors get 100% reflection.
Say they are cheap mirrors and only get 25% reflection.  So now we have Y amount of reflected light, which equals .25 X added to X right?

If this is correct (and it may not be) then did we not just create some additional photons?  I mean, it is not like the original X amount of light was diminished by 25% because we are now reflecting it right?  So do we now have 125% light instead of our 100% at the start?

We can't create energy so how does this happen?  More photons mean more energy right?

I had light and color as one of my college physics courses a long time ago and this was never discussed to my memory.

Even if my mirrors are so poor that they only reflect .1% of the light hitting them, that is still more light bouncing around that room than we started with...right?  Or, is this just a more "efficient" use of our original light source? (This may be the answer)

I am convinced that I am wrong here, we can not create more photons out of thin air...it just bothers me that I can not figure out how I am wrong.

Bill

[citfta]

Hi Bill,

I think I can explain it.  Or maybe not.  But I will try.  What you are surmising is what happens in a Laser.  Light is emitted by the lasing gases.   The light hits a mirror on one or the other end of the lasing chamber and is reflected back into the lasing chamber.  It then joins up with more light that was being produced while the first light was traveling to the end of the chamber and back.  So the energy of the first light emitted is added to the energy of the later light.  It appears to be an addition of energy and it is.  But the energy is added because the energy of the first light emitted was not use up by being absorbed into a material.  So it is still around for a while to be added to the later light energy.   Another way to think of it is putting water into a bucket with a drain on it to turn a small water wheel.  If we have the drain closed when we add a cup of water then that water gets added to the water already there and so on until we turn on the drain valve.  In your light example there is an increase in energy but only because the first energy is  not totally used up and is around to be added to the later energy.  I hope that makes sense.

Respectfully,
Carroll

PS:  I think I read somewhere you are in KY.  I am originally from there also.  Up near the Louisville area.

[Nink]

Research how a laser works. 

Edit
You beat me to it Carroll :-)

[Pirate88179]

Citfta and Nink:

Yes, I know how lasers work but I do not see the parallel here.  In a laser, you continually pump more and more energy into the system such that the photons flying back and forth between 2 mirrors gains enough energy to break through a mirror and then form a coherent beam.

I am talking about being in a small dark room, like a bathroom, and having 2 candles sitting on the sink in front of the mirror.  When you look at it by standing in front of the sink, you see 4 candles.  So, this is obviously more light then just from the 2 candles.  We did not add any more energy into the system like we do in a laser, all we did was to utilize a reflective surface.  So, this may fall into the category of just using the available light in a more efficient manner? 

Maybe a cool experiment would be to build a small, square box with mirrored surfaces inside on all sides.  Place an led into the box and fire it off once.
What happens to the photons?  Do they hit all of the mirrors and lose energy slowly and fade away?  Or, do they just lose their energy as if the mirrors were not there?  If they die out quickly then why does my very powerful led flashlight send photons thousands of feet up into the dark night sky?

Trust me, I realize these questions come from my lack of understanding and knowledge and not some new energy break through.  I do appreciate both of you taking time to answer.

Bill

PS  I was born and raised in NJ but have lived in south central KY for about 30 years.

[Nink]

Hi Bill Sorry not a field I have studied so an really don't understand,  The best I can offer is a scenario to demonstrate where the additional photons came from.

I think we all understands Photons are both a particle and a wave so they can either be absorbed by an object, pass through an object or be reflected by an object.

Mirrors will reflect anywhere from 70 to 95%+ of light depending on the material used but never 100% with the rest of the light being absorbed by the mirror. There are also two way mirrors and they work on a dark room light room concept with a % of light passing through the mirror. 


Take your bathroom and put a floor to sealing wall to wall mirror in the bathroom so you now have a room divided in half by your mirror with no light actually passing through the mirror. The light is either reflected or absorbed by the mirror and manifests as heat.


Light your two candles. Look in the mirror you see 4 candles.  The intensity of the second set of candles is now at 90% of the original candles (10% was absorbed by the mirror)

Now stand behind your mirror in the dark room.   What do you see ?

Take away the mirror.  What do you see ?