1. Post or give a link to the exact text you are referring to.kevinaltieri said:The Kirchhoff law of dependence of energy emitted from a blackbody only on wave length and temperature was demonstrated by Kirchhoff in a paper in the year 1859. The paper is in german naturally but I found it translated in english in a book of prof. Brace in 1901. A lot of time ago. But my question is, does somebody know this demonstration that to me seem really difficult to undestand? And could he explain in a different way this demonstration?
Kirchhoff's law on blackbody, also known as Kirchhoff's law of thermal radiation, states that the emissivity of a blackbody is equal to its absorptivity at a particular wavelength and temperature. This means that a blackbody will absorb and emit radiation at the same rate, making it a perfect emitter and absorber of thermal radiation.
Kirchhoff's law can be demonstrated through the use of a blackbody radiator. The radiator is heated to a specific temperature and placed in a radiation field. The emitted radiation is then measured at different wavelengths and compared to the absorbed radiation. According to Kirchhoff's law, the two values should be equal.
Kirchhoff's law is significant because it helps explain the behavior of thermal radiation and the concept of a blackbody. It also serves as the basis for the understanding of the relationship between a body's temperature and its radiation spectrum, which has many applications in fields such as astronomy and engineering.
Kirchhoff's law is closely related to the laws of thermodynamics, specifically the first and second laws. It is an extension of the first law, which states that energy cannot be created or destroyed, but can only be converted from one form to another. Kirchhoff's law also supports the second law, which states that the total entropy of an isolated system will always increase over time.
Yes, Kirchhoff's law can be applied to real-life scenarios. For example, it is used in the design of solar panels and other devices that use thermal radiation. It is also important in understanding the emission and absorption of radiation in stars and other celestial bodies, as well as in the production and detection of thermal radiation in industries such as manufacturing and energy production.