GPHY 102 Lecture Notes - Lecture 4: Electromagnetic Spectrum, Electromagnetic Radiation, Shortwave Radio

• School: Queen's University
• Department: Geography
• Course: GPHY 102
• Professor: Ryan K Danby

Document Summary

Electromagnetic radiation: omitted by all objects, energy that exists in waves, different types have different wavelengths and frequency. Frequency: waves per unit time: we only see a small portion of the electromagnetic spectrum and that is called the visible spectrum. Shortwave radiation: source is usually the sun, ultraviolet. Does not penetrate the atmosphere easily: visible light. Easily penetrates the atmosphere: near-infrared radiation: Just beyond the range of what we can see: shortwave infrared radiation. Longwave radiation: wavelength greater than 3 micrometers, middle infrared: from sun and combustion, longwave infrared: emitted by cooler bodies like heat. Remote sensing can help us see types of radiation we cannot otherwise (ie. near infrared) Thermal cameras pick up thermal longwave radiation. Two important principles of emission of em radiation. Inverse relationship between wavelength and temperature of objects emitting it: hot objects emit much more energy than cool objects. Solar energy: output peaks in visible light portion of spectrum.