Concerning the Physics of Light?

Question

If light consists of photons, whether they be vibrating strings, or "particles" of energy, what happens to it? For a hypothetical example: You have a light on in an enclosed room. If the light is absorbed into the surrounding matter (the walls) will there be any buildup of what the light is made from? If a photon changes physically and passes through the walls as something other than light, what becomes of it? On the other hand, if a photon contains only energy and no mass so that it just disappears after transferring its energy, how can it produce mass, such as an electron? I think in some ways string theorists have answers to these questions but parts of string theory are "way out there" and seem somewhat cultish. I tend to believe my eyes and things that can be tested. I'm just throwing this out there to see what your views are.

Answer 1

Photons are packets of energy. When the photons hit the wall, the energy is mostly converted to heat, raising the temperature of the wall slightly. Some photons bounce off the wall, with partail absorbtion which is why you can see the colors the wall is made from. The heat generated in the wall is partially reradiated as infrared photons which are not visible to the eye.
When photons hit your eye, they produce chemical and electrical changes which absorb the energy and the nerves transmit to your brain. The photons vibrations react with only some of the rods and cones in your eye depending on their energy spectrum and the nerves that react determine the color that you see.

Answer 2

If a photon is absorbed by an atom in a wall, there is no buildup of photons. In absorbing the photon, the electrons are put into a higher energy state and the photon completely disappears. If this interaction did not result in the photon disappearing, then the interaction could not occur (quantum physics). It is a transfer of energy. In a situation like this, it may be more intuitive to think of light as a wave. Remember, light has both wave and particle properties. Eventually the electron will settle back to its lowest energy state, which will re-radiate the energy it took from the original photon, sometimes as several photons each with less energy than the original, but so that the energy all adds up to be the same.

A photon will not change into anything else. It will either be absorbed by the wall or it won't. If it passes through the wall, it is still a photon and was never anything different as it passed through the wall. For a photon to suddenly become an object with mass, it would no longer be allowed to travel at the speed of light. Maybe this kind of thing can be induced in exotic situations, but not in everyday ordinary situations.

I'm not entirely familiar with string theory, but I don't think string theory predicts or asserts that photons can change into electrons. This is not possible.

The main premise of string theory is that everything in the universe can be described by one-dimensional strings that vibrate in multiple dimensions. The way they vibrate dictates what particle it is. It's all mathematical and may have no physical basis.

Anyway, I hope this helps.

Answer 3

Light is energy, and is represented as both a particle and a wave. Light hits the wall and is absorbed as energy, so that's why it gets hot after a while. Light is not vibrating strings - string theory has not yet been experimentally proven. Photons do not produce electrons. None of that is part of string theory. I think you don't really understand what it is.