Photoelectric effect and the light quantum
Efecto fotoeléctrico y cuanto de luz (fotón)
- Date
- 1905 · confidence high
- Place
- Patent Office, Bern, Switzerland
- Credited to
- Albert Einstein; Heinrich Hertz; Philipp Lenard
- People
- 👤 Albert Einstein1879–1955👤 Heinrich Rudolf Hernz1857–1894👤 Philipp Lenard1862–1947
- Field
- Cosmos & Earth
What was discovered
Einstein proposes that light is made of quanta of energy hν, thus explaining why the energy of the ejected electrons depends on frequency and not on intensity. It gives physical reality to Planck's quantum and reopens the corpuscular nature of light.
Millikan verified the equation in Chicago in 1916 while trying to disprove it.
What it led to
- Concept of the photon and wave-particle duality
- Quantum mechanics
- Photovoltaic cells and photodetectors
- Einstein's Nobel Prize (1921)
Built on
- Hertz's observation (1887) and Lenard's measurements (1902)
- Planck's quantum (1900)
Made possible
- Solar cell
- Photomultiplier
- CCD sensors and digital cameras