- The combined wave-like and particle-like properties of light are known as wave-particle duality.
- Electromagnetic radiation is frequently characterised as waves. However, the energy delivered by these waves is absorbed at specific points, similar to particle absorption.
- The energy absorbed from an electromagnetic wave is known as a photon, representing the smallest possible quantity of light (quanta).
- When a light wave is absorbed as photons, the energy of the wave concentrates at certain points. These points are where the photons are found. This is known as wave function collapse.
- The wave-particle duality is not just limited to light but also applies to other particles like electrons.
- The double-slit experiment is a classic demonstration of wave-particle duality.
Albert Einstein wrote:
It seems as though we must sometimes use the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do.