AST-1002 Chapter 3: AST Chapter 3
Document Summary
The value c is a fundamental property of the universe. The speed of light appears in equations that describe, among other things, atoms, gravity, electricity, magnetism, distance, and time. Shorter wavelengths of light can knock some electrons off the surfaces of metals, while longer wavelengths of light cannot, no matter how intense the beam of long-wavelength light. Some colors (or, equivalently, wavelengths) can remove the electrons and others cannot, the electrons must receive different amounts of energy from different colors of light. Einstein proposed that light travels as waves enclosed in discrete packets, now called photons, and that photons with different wavelengths have different amounts of energy. Specifically, the shorter the wavelength, the higher a photon"s energy. Photon - a discrete unit of electromagnetic energy. If you count the number of wave crests that pass a given point per second, you have found the frequency of the photon.
