Robert Andrews Milliken

Robert Andrews Millikan was an American experimental physicist who won the Nobel Prize in Physics in 1923 for his work on the elementary charge of electricity and the photoelectric effect. He is best known for his famous oil-drop experiment in 1910, which measured the charge of the electron, and for verifying Einstein's photoelectric effect equation. Millikan also conducted pioneering research on cosmic rays and served as a director at the California Institute of Technology.