1. The problem statement, all variables and given/known data The particle nature of light is best illustrated by which of the following? 1) The scattering of alpha particles from gold foil. 2) The fact that hot objects emit electromagnetic radiation. 3) The diffraction pattern observed when a beam of electrons is scattered by a crystal 4) The fact that a rainbow consists of a continuous spectrum of colors. 5) The ejection of electrons from a metal surface illuminated by light. 2. Relevant equations 3. The attempt at a solution My guess is #5 or #2, because they both have to do with electrons changing energy levels and emitting (or absorbing) electrons.