When light comes across with a solid material, some of it is reflected, some of it passes through and some of it is absorbed. I understand the reflection and passing through, but I don't understand what happens when light is absorbed.
Suppose that there is an enclosed box. Its material is thick enough so that no light can escape out. We put a Led diode in it whose internal resistance is zero (there is no loss as heat energy, all energy dissipated is given out as light). What are the possible steady state scenarios that can happen?
Why and how some wavelengths of sun light heats up black objects while some other wave lengths do not?
Why and how some wavelengths of light pulls the outer most electrons of atoms to higher energy levels while other wavelengths have no such effect? (I understand that energy of a photon must be enough to take electron to higher energy level, but why doesn't it take the electron temporarily a littler higher in the current energy level and then make it return back? I understand that an electron cannot stay between two energy levels, because those are unstable regions; but why doesn't electrons stay there even if it is as short as an instant?)