CEM 141 Lecture Notes - Lecture 14: Radiography, Photon
Document Summary
Wavelength and frequency are inverse of each other. Short wavelengths (and high frequency) em radiation is higher in energy . Problem: wave nature of light does not explain some phenomena. Many metals emit electrons when electromagnetic radiation shines on the surface. The light is transferring energy to the electrons at the metal surface-where it is transformed into kinetic energy that give the electrons enough energy to leave the atoms in the metal. Uses photomultipliers, photocells, garage door openers. Why does adding energy in the form of light (em radiation) allow electrons to escape . When you increase the intensity of uv light the number of electrons emitted increases. When you keep the intensity the same and increase the wavelength (decreasing the frequency) to the blue the number of electrons emitted decreases. When you keep the intensity the same and increase the wavelength (decreasing the frequency) into the yellow no more electrons are emitted.
