Light beam,mirror question

If i put a lazer pointer in a vaccum cube and the inner surface of the box is all


I turn it on and off it in one second.

Shouldnt the beam be reflecting for unlimited times and the inside of the cube is

bright forever?

*the cube is vaccum

I know it is false but how come... The beam should not lose energy when bouncing off the mirrors in theory?

Thank you very much :/

2 Answers

  • 天同
    Lv 7
    7 years ago
    Favorite Answer

    There is no perfect mirror. On reflection on a surface, part of the incident light energy is reflected, but part of it is absorbed. Hence, the brightness inside the cube would gradually dies down, though this may take a long time on well polished mirror surfaces.

  • Anonymous
    7 years ago



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