Some Laws Related to Electromagnetic Radiation


1.    Molecules which "possess" internal energy "possess" temperature. (Quotes mean term is scientifically-improper and only used as an analogy.)


2.    Any object which possesses internal energy also emits another type of energy known as ELECTROMAGNETIC RADIATION (or radiation for short).


       (Note: an alternate but equally accurate definition for radiation is-->that process by which electromagnetic energy is transmitted without the aid of a physical substance.)


3.    The hotter an object (that is, the more internal energy it possesses), the greater the amount of radiation emitted (referred to as irradiance, or energy flux density,or radiant flux or radiation intensity) .(Stefan-Boltzmann Equation)


4.    The hotter an object, the shorter the wavelength of radiation it emits. (WienÕs Equation)


Some Concepts Related to Temperature Change


1.    Any object absorbing radiation, will gain internal energy.


2.    Any object left to itself will emit electromagnetic radiation at the "expense" of its own internal energy.


3.    The actual temperature change experienced by an object can be understood on the basis of the inputs (factor (1) above) and outputs (factor (2) above).  This is known as the ENERGY BUDGET approach.