What principle states that any ray of light subjected to reflection or refraction can be traced in reverse by a ray in the opposite direction?

The principle of reversibility of light.

Explanation:

The principle of reversibility of light states that the path of a ray of light is reversible. If a ray of light, after suffering a number of reflections and/or diffractions, is allowed to fall normally on a mirror, it retraces its path along reverse direction.

answer: i'm not sure which is which for i get confused on it all the time but i can tell you that the answer lies with the convex and concave devices. i hope this you. have a good day and best of luck to you!

explanation:

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it