* Wave theory cannot explain the Compton effect: The wave theory of light predicts that the scattered light should have the same frequency as the incident light, regardless of the scattering angle. However, the Compton effect shows that the scattered light has a *lower* frequency (longer wavelength) than the incident light, and the amount of change depends on the scattering angle.
* Particle theory explains the Compton effect: In the particle picture, the Compton effect is explained as a collision between a photon and an electron. During this collision, the photon transfers some of its energy and momentum to the electron, resulting in a lower energy (longer wavelength) photon. The amount of energy transferred depends on the angle of scattering.
Key observations supporting the particle nature of light in the Compton effect:
* Energy and momentum conservation: The Compton effect demonstrates that the total energy and momentum of the system (photon and electron) are conserved, which is expected in a particle collision.
* Angle-dependent scattering: The change in wavelength (or frequency) of the scattered photon is dependent on the angle of scattering, as predicted by the collision of particles.
* No classical explanation: The wave theory of light cannot explain the angle-dependent scattering and the change in wavelength observed in the Compton effect.
Therefore, the Compton effect is a crucial piece of evidence supporting the particle nature of light. It highlights the duality of light, meaning it can exhibit both wave-like and particle-like behavior depending on the situation.
