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Q & A: trapped light waves

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Most recent answer: 07/10/2008
Q:
Although this sounds like a silly question, from my understanding of light, I would guess that if you had a box covered in mirrors you would be able to trap light inside the box, is this indeed correct? Also on the same topic of light, what exactly about light travels in waves?
- Paul (age 14)
Canada
A:
Mirrors are never perfect. They always absorb a little of the light that hits them. Extremely high quality mirrors can let light bounce off them 100 times or so before it's mostly absorbed. Since light travels very fast, it hits the walls of a little box very frequently.  It's hard to trap light this way for even a millionth of a second.

On waves: light consists of electromagnetic waves. Everything about it travels in waves. I suspect I'm missing your question somehow, so feel free to follow up.

Mike W.

(published on 07/08/2008)

Follow-Up #1: electromagnetic waves

Q:
I think by my latter question concerning the wave I'm trying to figure out what my teacher meant when he talked about magnetic waves go horizontally and electric vertically (could be other way...dont' remember clearly).
- Paul (age 14)
Canada
A:
Aha, I'm starting to get it. As the wave travels, the electrical and magnetic fields point at right angles to each other and both directions are at right angles to the direction the wave is going. You can have linearly polarized waves, with all the electrical field in one plane and the magnetic fields in a plane at right angles. You can also have circularly polarized waves, with the directions of both types of field spiraling around. You can also have various intermediate forms.

Mike W.

(published on 07/10/2008)

Follow-Up #2: perfect reflectors?

Q:
I'm following up again because I just thought of somthing along the same idea. Is there theoretically a "perfect mirror" and "perfect black" as in absorbing all light?
- Paul (age 14)
Canada
A:
You can certainly have perfect absorbers- a just plain vacuum works. If you put any sort of material there, there will always be a little reflection. I don't believe that any material is an absolutely perfect reflector.

Mike W.

(published on 07/10/2008)

Follow-up on this answer.