How did quanta explained black body curves (1 Viewer)

blackbunny

Member
Joined
Mar 17, 2004
Messages
466
Gender
Male
HSC
2004
I don’t understand how did the quantisation of energy explained the radiation curves for black body
 

tennille

...
Joined
Nov 2, 2003
Messages
3,539
Location
Sydney
Gender
Female
HSC
2004
Join the club- I just accepted it. Just say that PLanck stated it was quantised using the relationship of E= hf. You'd think by putting a higher frequency in the formula would give you a larger result.
 

helper

Active Member
Joined
Oct 8, 2003
Messages
1,183
Gender
Male
HSC
N/A
The UV catastrophe is the drop off in energy at the high frequency, low wavelengths.

Plank came up with his law to mathematically model the curve but did not understand the meaning.

By the idea of quanta you need to remember the whole or nothing principle.
For a UV quanta to be released a large amount of radiation is required at one instant in time. Statistically this is not going to occur very often, so there are few of these quanta produced and for this reason little radiation of high f.
 

Xayma

Lacking creativity
Joined
Sep 6, 2003
Messages
5,953
Gender
Undisclosed
HSC
N/A
The UV catastrophe was the classical theories problem, the idea that as the shorter the wavelength the more radiance there should be reaching the problems of infinities.

Some drops are more likely to occur then other, such as the brighter lines in the hydrogen spectrum.

The highest drop however is limited by the escape energy required in hydrogen this is 13.6eV

The smallest change is near 0 since they normally move a little in the shells, which accounts for the trailing off.
 

blackbunny

Member
Joined
Mar 17, 2004
Messages
466
Gender
Male
HSC
2004
So from what I know now, to explain how it is possible to release low energy at high f there are just not many quanta. Meaning like 1 dose of high radiation (low temp) will not get u killed but a lot (lots of quanta) will. So there are basically not enough matches (quanta) to light the fire (give off high temperature) :)
 

fush

Member
Joined
Feb 11, 2004
Messages
441
Location
Sydney
Gender
Male
HSC
2004
i thought it was something to do with the size of the energy packets being so small that once reached a certain wavelength cant get any smaller and hence the radiance (intensity) of the curve must drop back down...but im not sure

can anyone confirm this?
 

snoopwogg

Member
Joined
Feb 4, 2004
Messages
74
Location
Guantanamo Bay
Gender
Male
HSC
2004
aAs the temperature became hotter, the walls of the cavity absorbed many packets of energy and released them as one bigger bundle of energy with a higher frequency. hence, the intensity of those bundles decreased as the frequency increased. That is, a smaller number of protons have larger energies, correspoing to lower intensities. :D
 

Danny11

Member
Joined
Oct 24, 2004
Messages
37
Xayma said:
The highest drop however is limited by the escape energy required in hydrogen this is 13.6eV

The smallest change is near 0 since they normally move a little in the shells, which accounts for the trailing off.
could you expand on that, I'm not quite understanding it.
 

superbird

Member
Joined
Feb 10, 2004
Messages
774
Location
sydney
Gender
Male
HSC
2004
Danny11 said:
could you expand on that, I'm not quite understanding it.
dont worry. just know the basic concept. i've never heard of this hydrogen explanation before and i dont think its in my textbook
 

Danny11

Member
Joined
Oct 24, 2004
Messages
37
the books are not explaining, they are waffling. then again, if that gets me the marks its all good.
fush said:
i thought it was something to do with the size of the energy packets being so small that once reached a certain wavelength cant get any smaller and hence the radiance (intensity) of the curve must drop back down...but im not sure
why can't the wavelength get any smaller, is the wavelength also quantised?
 

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

Top