Developing Theories of EM Radiation
Isaac Newton (1672)
- Newton proposed that visible light is a stream of microscopic particles called corpuscles
- However, these corpuscles could not explain interference or diffraction effects, therefore, the view of light as a wave was adopted instead
Christiaan Huygens (1678)
- Huygens came up with the original Wave Theory of Light to explain the phenomena of diffraction and refraction
- This theory describes light as a series of wavefronts on which every point is a source of waves that spread out and travel at the same speed as the source wave
- These are known as Huygens' wavelets
- Young devised the famous double-slit experiment
- This provided experimental proof that light is a wave that can undergo constructive and destructive interference
James Clerk Maxwell (1862)
- Maxwell showed that electric and magnetic fields obeyed the wave equation. This means that light was simply waves made up of electric and magnetic fields travelling perpendicular to one another
- Later, Maxwell and Hertz discovered the full electromagnetic spectrum
- Einstein discovered that light behaves as a particle, as demonstrated by the photoelectric effect
- He described light in terms of packets of energy called photons
- Later the scientific community came to understand that light behaves both like a wave and a particle
- This is known as wave-particle duality
