kanato said:In the Compton effect the photon cannot be completely absorbed because momentum and energy must be conserved.
kanato said:Work out the change in energy and momentum if the photon is completely absorbed:
Initial energy is energy of photon plus rest energy of electron (p is momentum of photon):
[tex]E_i = pc + mc^2[/tex]
Final energy is entirely the electron (p is now momentum of the electron):
[tex]E_f = \sqrt{(pc)^2 + (mc^2)^2}[/tex]
Set them equal and square and you get:
[tex](pc)^2 + 2 pmc^3 + (mc^2)^2 = (pc)^2 + (mc^2)^2[/tex]
Cancel terms until you get p = 0. This tells you that energy and momentum can only both be conserved if the photon has zero momentum, and hence zero energy, so there is no physically meaningful result.
Red_CCF said:Why would the collision be inelastic if the photon is completely absorbed?
The photoelectric effect is a phenomenon where electrons are emitted from a metal surface when it is exposed to light of a certain frequency. This effect was first observed by Heinrich Hertz in 1887 and later explained by Albert Einstein in 1905.
The photoelectric effect shows that light behaves like a stream of particles, known as photons. This is because the number of electrons emitted from a metal surface depends on the intensity of the light, not the frequency. This is in contrast to the wave nature of light, where the frequency would determine the energy of the electrons emitted.
The Compton effect is a phenomenon where X-rays lose some of their energy when they collide with electrons in a material. This was first observed by Arthur Compton in 1923 and provided evidence for the particle nature of X-rays.
The Compton effect shows that X-rays behave like particles, as they can transfer some of their energy to electrons during a collision. This supports the idea of photons, which are packets of energy that make up electromagnetic radiation.
The Photoelectric and Compton effects are significant because they provide evidence for the particle nature of light and X-rays, which was a major breakthrough in understanding the behavior of electromagnetic radiation. These effects also have practical applications in technology, such as in photoelectric cells used in solar panels and in medical imaging techniques like Computed Tomography (CT) scans.