blackbody (1 Viewer)

[stag_j]

quick question... had my trial yesterday and i was sooooo surprised how easy it was... hadn't studied nearly enough and yet answered everything with reasonable confidence.
anyway, one of the multiple choice questions caught me out and it's bugging me now
it was something along the lines of two boxes, acting as blackbodies, one made from aluminium, one from copper.
i forget which way round it was, but one of them has better thermal conductivity
question asked was what can be observed by measuring the wavelength of the light emitted through the hole:
a) no radiation emitted
b) copper has longer wavelength
c) aluminium has longer wavelength
d) both the same

 

[gnrlies]

yeah thats a tricky one..

My thinking is this... (i dont know if im right or not..)

I would of said that the one that wasn't as good with thermal conductivity would produce longer wavelengths

This is becuase as the better thermal conductivity would allow a wider range of the spectrum to be released as radiation at shorter and longer wavelenghts, whereras the body with not as good thermal conudctivity would only release the larger wavelenghts assosciated with lower temperatures (the black body would not be able to emit the shorter wavelenghts becuase of this) achieved within the black body.

As I said I dont know if this is accurate, but if I had to decide thats how I would go...