Black body HELP! (1 Viewer)

externalfire

New Member
Joined
Apr 10, 2007
Messages
9
Gender
Male
HSC
2008
Hi... I know first of all that alot of people have asked the same questions...
THe problem is i have read them.. and still dont understand -_-

I am alittle thick headed..

Anyone can someone PLEASE help me with black body...

THere are a couple of areas i just can grasp.

First off is the phenomena when wavelengths decrease why cant intesity reach infinity?
I mean. When a wavelength decreases doesnt that meant the frequency of the wave increases? So doesnt that just mean that the energy of the wave increases and even to infinite? HOw does this violate the principle of conservation of energy?

Secondly. I understand that energy is recieved and transmitted as quanta (packets of energy) what i dont understand is why is there a peak of intensity? Why does the particles in the black body stop absorbing radiation at that certain wavelength? Is it becasue it has such a high frequency? If that was the case wouldnt it mean that the graph would just drop because of the "All or nothing."


I know the two questions are actually a heap of questions.. BUT PLEASE
i have been trying to understand this but my teacher just goes "deal with it." WELL I BLOODY CANT!

thank you in advanced
 

ronnknee

Live to eat
Joined
Aug 2, 2006
Messages
474
Gender
Male
HSC
2008
For the first question, one aspect of the answer would be that the classical theory (ie. as wavelength decreases, the radiation increases) does not fit with the experimental results. If the results say they don't, then they just don't
 

chaarii

New Member
Joined
Jan 3, 2008
Messages
16
Gender
Female
HSC
2008
Hey

I don't know if this answers your questions, I just copied and pasted from my physics notes lol.. sorry if it doesn't. Hope it helps!

Black Body
· One which absorbs all incoming radiation
· Energy spread throughout the object
· As they absorb radiation, their temperatures increase
· As the walls of the cavity get hotter, the emission of more intense, shorter wavelength radiation from the cavity occurs
· The energy absorbed is released as the blackbody falls in temperature, back down to room temperature
· Experimental data showed that the radiation intensity curve corresponding to a given temperature has a definite peak or maximum, then declining
· Classical wave-length theory of light predicted that as the wavelength of the radiation emitted becomes shorter, the radiation intensity would increase without limit
· This meant that as the wavelength decreased, intensity of emitted radiation would approach infinity violating the principle of conservation of energy è “Ultraviolet catastrophe”
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top