Emissivity of radiation from a surface, Leslies cube

[rayman123]

Homework Statement

Hello! I am going to do a demonstration involving the Leslie's cube to demonstrate the emissivity of a thermal radiation from different surfaces. I have been reading some about black body radiation which has emissivity = 1 but this is not the case. Leslie's cube has 4 surfaces but could someone explain to me why the black surface emitts the most of the radiation and the silver one least?

Thank you!

Homework Equations

The Attempt at a Solution

 

[Antiphon]

Black surfaces absorb, silver or white surfaces reflect.

The absorption and emission processes are symmetrical. This means a good absorber is a ready emitter.

For the white or silvet surface pretend the energy to be emitted is just inside the cube. The silver surface will reflect the energy back into the box, so low emissivity.

 

[rayman123]

yes I know that but I would like to know what is the physical explanaition for it? what makes that the black one emitts the most? why it has the highest emissivity ?

 

[drames88]

i just did experiment on Leslie's cube, but can not often answer 1 question: which says, what is the advantage and disadvantage of my device in every day life situation. can someone please help me with this!