Question

Imagine there is a solid cube made of non absorbent material. A light bulb is fixed inside the cube with the material covering it from all directions. The switch of the bulb is outside the solid cube. When we turn on the bulb and then turn it off, where would the light go?

Answer 1

Light is the form of energy it's get absorbed by the wall is heat.The wall is a solid, which consists of a (fairly) regular structure of atoms. just imagine a grid of hard spheres laying against each other this is the surface of the wall. at absolutely zero, these atoms do not move and are simply at rest , one just touching the next. Having a temperature means that the wall contains heat thermal energy