Can you get light into a room made of two-way mirrors?

Question

My question is this. If I have a room, or even a small box that is completely sealed off from light except for one wall (or side of the box) that is a two way mirror, can light get into the box. My first thought was that we could see into the box, but the people/ants whatever, would be in darkness.

But then I thought, if the people on the outside can see in, the light would go into the box and therefor the people inside the box would be able to see too.

So what if the mirror was the other way around? Obviously, people on the outside couldn't see in, but could the people on the inside; see out? They would have a window that see blackness right? Mirrors reflect about 99.99% of light (could be wrong) right? so would the people inside have a window that would appear dark outside, despite the fact it's light outside?

Answer 1

A two way mirror is a window between a light room and a dark room. The side with light on it sees a mirror. The other side sees a window. Light passes from the light side to the dark side, but doesn't pass back the other way.

Tonight, look out your window into the darkness (unless you live in a city like me where its still light outside your window at night). You'll see your reflection in the window. The more light inside and the less light outside, the more you'll see your reflection and the less you'll see outside. Likewise, with the same window, if you look in from outside on a bright day with the lights off inside, you see a reflection, but from inside you can see out with no problem. Note that there is no perfect 2-way mirror, as some light passes through, and so there must be some light on both sides, but the brighter one side is and the darker the other, the better you'll have this effect.

Your set-up wouldn't be possible. If you had the lights on in the wrong room, it would switch which way the two way mirror goes. I think your little thought experiment just proved that it's only possible in that one direction.

Answer 2

The people inside the room would see the outside clearly while the people outside would only see a mirror.

Just look through the windows in your own home at night when you turn on the lights as opposed to when you turn off your lights.