This question already has an answer here:
If you have 2 mirrors over for each other placed exactly so they face each other perfectly, and then use a laser light pen as the source into one of the mirrors so it bounces to the other mirror and back again:
- Would the laser light line continue to exist between the 2 mirrors if the source of the laser stopped?
- If so, how long could the laser light continue to be between the mirrors without a source?
- Would it just continue existing between the mirrors using itself as the source or is this not possible for light?
Note: It doesn't have to be only 2 mirrors. It could be any amount of mirrors if that would change the outcome.