# Two way mirror on the side where you can see through it

1. Dec 26, 2008

### x G r E e D

Lets say you are looking through a two way mirror on the side where you can see through it, and there is a mirror on the other side. What would you see? So there is two mirrors back to back and you can see through one of them. So when the light bounces off the first mirror and trys to go back through to where you are, and it theoreticaly can't because its only a two way mirror.

2. Dec 26, 2008

### Staff: Mentor

Re: Light

Why can't the light reflected from the first (regular) mirror pass through the two way mirror? (It wouldn't be of much use if light couldn't pass through it!)

3. Dec 26, 2008

### calvinuk

Re: Light

Wouldn't you see your own reflection?

4. Dec 26, 2008

### Staff: Mentor

Re: Light

Assuming an ideal one-way mirror (perfectly transparent one direction and perfectly reflective the other so that light only goes one way, towards you), then you would see nothing.

Assuming a real one-way mirror (partially transparent and partially reflective both ways), then you would see a dim reflection of yourself.

5. Dec 26, 2008

### x G r E e D

Re: Light

No because light cant pass through the mirror that you are looking through towards you. If you were on the other side yourself. Think of it as if you were at a police station in an interogation room where you are the cop looking at the suspect, and he cant see you. Put a mirror where the suspect is and then what will see. Probably nothing since the light cant pass through it. Therefore you see a cancelation of light waves making it black.

6. Dec 26, 2008

### Staff: Mentor

Re: Light

It's still not clear to me what you are asking about. There are two sides/rooms to the 2-way mirror setup:
-The subject side (this is where the subject or suspect is placed; this room is kept brightly lit);
-The observer side (this is where an observer would sit; this room is kept dim)
You added a regular mirror to the subject room, I presume. What will who see? Who's looking at that mirror? The suspect? The observer?
The observer viewing things from behind the 2-way mirror sees the light from within the subject room (a portion of that light is transmitted through the 2-way mirror). So he sees whatever's in the room reflected off the regular mirror.

Since a bit of light from the observation room is transmitted through the 2-way mirror into the subject room (hopefully not noticed by anyone in there!), the observer might be able to see a dim reflection of himself in the regular mirror, as DaleSpam noted.