Black body radiation help please, 10 points?

Question

Black body radiation help please, 10 points?

Answer 1

try re-asking this question during the black history month

Answer 2

It never ceases to amaze that people don't ask Wiki when there are so many full answers there.

Answer 3

During the later years of the nineteenth century, physicists were attempting to calculate the energy distribution of the radiation emitted by a cavity known as a blackbody. A blackbody is a cavity that is a perfect absorber and emitter of radiation and has a radiation spectrum that depends upon its absolute temperature. Many theorists attempted to use 'classical' physics to account for the spectrum but they were only partially successful. Some of the theories predicted that at the high-energy end, of the blackbodies’ spectrum, infinite energies would occur in a phenomena dubbed the ‘ultra-violet catastrophe’.



In 1900, Max Planck solved the blackbody energy, distribution problem by postulating that energy came in small discrete packets or quanta rather than the classical continuous and infinitely dividable. Using the concept, he derived a partition function that correctly described the radiation energy distribution of a blackbody cavity.



The blackbody concept is a theoretical one and therefore a 'silver', bronze or green (etc..,) surface may be approximated by the equation of radiation energy distribution for the given temperature of the surface, namely: -



Planck's law states that



I(ν,T) dν = 2hν³..... 1 ..... dν

................ __ ________

..................... hν/kT

................ c² (e . - . 1)



where (the dots are formatting place holders)



I(ν,T) dν is the amount of energy per unit surface area per unit time per unit solid angle emitted in the frequency range between ν and ν + dν by a blackbody at temperature T;

h is the Planck constant;

c is the speed of light in a vacuum;

k is the Boltzmann constant;

ν is frequency of electromagnetic radiation; and

T is the temperature in kelvins.

Answer 4

Are you the laziest or stupidest student on the Ask site?

Answer 5

The particles in it change the other particles it effects.



Hope this helped. :(

Answer 6

In physics, a black body is an idealized object that absorbs all electromagnetic radiation that falls on it. No electromagnetic radiation passes through it and none is reflected. Because no light (visible electromagnetic radiation) is reflected or transmitted, the object appears black when it is cold. However, a black body emits a temperature-dependent spectrum of light. This thermal radiation from a black body is termed black-body radiation.[nb 1]

At room temperature, black bodies emit mostly infrared wavelengths, but as the temperature increases past a few hundred degrees Celsius, black bodies start to emit visible wavelengths, appearing red, orange, yellow, white, and blue with increasing temperature. By the time an object is white, it is emitting substantial ultraviolet radiation.

The term "black body" was introduced by Gustav Kirchhoff in 1860.





Technically, if you coloured the surface of a black body, it would exhibit different behaviour, so it wouldn't be a black body. Painting it silver would mean it would absorb less energy and therefore radiate less energy at longer wavelengths.

Source(s):

http://en.wikipedia.org/wiki/Black_body