Illustration of vibrations of a drum.
Image via Wikipedia

Lord Rayleigh on classical limes made an attempt to explain the energy distribution in black body radiation, which was completed by Jeans in 1900. The result obtained by then is known as Rayleigh – Jean’s Law.

Black body emits radiation of continuously variable wavelength right from zero to infinity. This radiation can be imagined as broken up into monochromatic waves. These monochromatic waves originate as a result of a different modes of vibration of the medium, which at that time was supposed to be an electromagnetic sensitive medium called ‘ETHER’ According to well-known result of statistical mechanics, the number of such modes of vibration lying between the wavelength range $ \lambda $ and $ \lambda+d\lambda $ is equal to $ 8\pi{\lambda}^{-4}d\lambda $ per unit volume. And also according to the theorem of equipartition of energy, the total energy of a system for each mode of vibration (or degree of freedom) is equal to $ kT $ , where $ k $ is the Boltzmann constant and $ T $ is the temperature of the system in Kelvin. Hence the total energy of the radiation lying between the wavelength range $ \lambda$ and $ \lambda + d\lambda $ per unit volume is
$ u_{\lambda}d\lambda$ =number of mode of vibration $ \times kT $
or, $ u_{\lambda}d\lambda=8\pi kT{\lambda}^{-4}d\lambda $
This is Rayleigh Jean Law.

Total
0
Shares


Feel free to ask questions, send feedback and even point out mistakes. Great conversations start with just a single word. How to write better comments?
1 comment
Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

You May Also Like

Consequences of Light Absorption – The Jablonski Diagram

All about the Light Absorption’s theory on the basis of Jablonski diagram. According to the Grotthus – Draper Law of photo-chemical activation: Only that light which is absorbed by a system, can bring a photo-chemical change. However it is not true that all the kind of light(s) that are absorbed could bring a photo-chemical change. The absorption of light may result in…

Statistical Physics: Ensembles

Ensembles As a system is defined by the collection of a large number of particles, so the “ensembles” can be defined as a collection of a number macroscopically identical but essentially independent systems. Here the term macroscopically independent means, as, each of the systems constituting an ensemble satisfies the same macroscopic conditions, like Volume, Energy, Pressure, Temperature and Total number…

Albert Einstein and His introduction to the Concept of Relativity

Albert Einstein This name need not be explained. Albert Einstein is considered to be one of the best physicists in the human history. The twentieth century has undoubtedly been the most significant for the advance of science, in general, and Physics, in particular. And Einstein is the most luminated star of the 20th century. He literally created cm upheaval by…

Fox – Rabbit Chase Problems

Part I: A fox chases a rabbit. Both run at the same speed $ v$ . At all times, the fox runs directly toward the instantaneous position of the rabbit , and the rabbit runs at an angle $ \alpha $ relative to the direction directly away from the fox. The initial separation between the fox and the rabbit is…

Symmetry in Physical Laws

‘Symmetry’ has a special meaning in physics. A picture is said to be symmetrical if one side is somehow the same as the other side. Precisely, a thing is symmetrical if one can subject it to a certain operation and it appears exactly the same after the operation. For example, if we look at a base that is left and…