GEOB 102 Lecture Notes - Lecture 2: Electromagnetic Radiation, Radiant Energy, Energy Economics

• School: UBC
• Department: Geographical Biogeosciences
• Course: GEOB 102
• Professor: Simon Donner

Document Summary

One measure of energy is force applied to an object over some distance. Radiant energy in the form of electromagnetic waves, is emitted at the speed of light by all objects with a temperature above absolute zero (-273 degree c) A wavelength (l) is the distance from one wave crest to the next. The frequency is the number of waves that pass a point per unit time. Shorter wavelengths equal higher frequency (i. e. the wave energy is more concentrated) ***electromagnetic spectrum: cosmic rays, y-rays, x-rays, ultraviolet light, ( shorter) visible light (longer ), infrared radiation, microwaves, radio waves. Two important principles govern the emission of electromagnetic radiation: remember these. Stefan-boltzmann law: hot objects radiate more energy at all wavelengths than cooler objects. Wien"s law: the hotter the object, the shorter the wavelength of peak radiation (the peak of the wavelength is shorter) (more ultraviolet for hotter) These laws apply only to a perfectly radiating surface known as a black body.