Perfect" Radiators & Absorbers: Why Materials Differ

[pkc111]

Why are some materials behave more like black-bodies than others?
What does it mean a "perfect" radiator and absorber? All objects give off 100% of the heat energy given to them eventually if they are at the same temperature as their environment...right?

 

[DrClaude]

Why are some materials behave more like black-bodies than others?

A blackbody is an idealized object. Real objects will not absorb all wavelengths equally.

What does it mean a "perfect" radiator and absorber?

It means 100% absorption at any wavelength (no reflection). Perfect emission corresponds to the blackbody spectrum.

All objects give off 100% of the heat energy given to them eventually if they are at the same temperature as their environment...right?

Yes, but an actual object will not emit following the exact blackbody curve. Some wavelengths will be favored with respect to others.

 

[pkc111]

Thanks a lot that makes sense!