Quantum Physics Study Guide

Quantum Physics Study Guide There have been two models of light. What are they and who first supported each? Particle: Newton and wave: Huygens (1600s) What determines the color with which a body glows? temperature What is Planck's equation? E=hf What does Planck's equation mean? Energy comes in discrete packets. Energy of a photon is proportional to its frequency. What does Planck's equation explain? Blackbody radiation problem and the photoelectric effect What is Planck's constant (both what does it mean and what is its value)? 6.63x10-34 Js,(very small) it is the proportionality constant relating a photon's energy and frequency. What is a quantum? Small packet (of energy) What is a photon? Quantum of light or particle of light What is the photoelectric effect? Emission of electrons from a metal when struck by certain frequencies of light. Why can't low frequency light cause the emission of electrons, regardless of the intensity of the light? The energy per photon is too low to get electrons away. Why does higher intensity high frequency light emit more electrons than low intensity high frequency light? Because high intensity light has more photons. How did Einstein explain the photoelectric effect? Used Planck's idea of energy coming in packets (see photoelectric diagrams from notes) What is Einstein's photoelectric effect equation? KE = hf - φ What does Einstein prove about light using the photoelectric effect? IT IS A PARTICLE. How does Einstein's proved statement about light using the photoelectric effect compare to Young's experiment and model of light? It apparently contradicts him. Is light a particle or a wave? Explain. YES. Light travels as a wave and hits like a particle. Light is a particle; light is a wave... the truth lies in the tension over the semicolon. What are the building blocks of an atom? Protons, neutrons, electrons Which particles are in the nucleus of an atom? Protons and neutrons In the Bohr model of the atom, what is the position of the electrons? At specific radii How is this similar to and different from Rutherford's model? Similar because electrons orbit nucleus. Different because in Bohr's model, electrons only allowed at specific radii. What model did DeBroglie propose for the electron? Electron is a WAVE.