light properties

[mr. piper]

as i see it, energy can neither be created or destroyed. light is a form of energy, so where does the energy go if light were to be shone into a sealed box that is coloured black on all surfaces? will the mass of the box be greater after the light is on?

[brachiopod]

The light would be absorbed by the black surfaces and be converted into kinetic energy by virtue of increased vibration of its atoms. In other words it would heat up.

You don't say whether the box is insulated or not. If not, the heat would be dissipated to the outside by conduction and radiation. If insulated, the surfaces would just continue to heat up.

(There would be some re-radiation and re-absorption of energy going on within the box, but this can be ignored in this scenario)

The mass of the box is not affected.

( 1kg of water at 0 oC has the same mass as 1kg of water at 50 oC)