| MadSci Network: Physics |
The short answer to your question is ..... yes, light is a wave or a particle. The slightly longer answer is that it has wave-like properties and particle-like properties in different situations. If it is striking a metallic surface and kicking out electrons from the atoms, it has a particle behavior. Any given wavelength of light will always transfer the same energy to the atoms and the electrons will all have the same kinetic energy. If it is striking a diffraction grating it will behave like a wave. Planck and Einstein provided separate but complementary theoretic explanations, both in 1905, for two different sets of phenomena. Planck characterized the spectrum of black-body radiation (Planck's Law) and Einstein developed a quantum explanation of the Photoelectric effect that required that light be in discrete packets of energy, E=h times nu, where h is Planck's constant and nu is the frequency. Planck later was awarded the Nobel in 1918 and Einstein in 1921. Check this site for historical details: Einstein DeBroglie described how electrons should also have the dual particle-wave aspect and received the Nobel for that work in 1927 which was also the year in which that prediction was experimentally confirmed. See DeBroglie
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