AQA A Level Physics复习笔记3.3.4 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

   

Thomas Young (1801)

• 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

Albert Einstein (1905)

• 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