quantum physics

• Emissions of electrons from a metal surface when electromagnetic is incident on electrons is called a photoelectric effect
• minimum energy required for an electron to leave a surface is called the work function
• photons are a discrete packet of energy which depend upon frequency of electromagnetic radiation as an electron can absorb only a single photon of energy at a time


  what does the proton model explain?
• The minimum frequency needed to produce photoelectron emission is known as threshold frequency
• the proton model explains that light consists of particles known as photons, with different frequencies corresponding to different energies.
• The wave-particle duality principle states that all matter exhibits both particle-like and wave-like properties simultaneously.
• Electron diffraction experiments showed that electrons behave like waves and have wavelengths associated with them.
• Electrons emitted by light with frequencies greater than the threshold frequency will be accelerated away from the metal surface by the electric field produced by the positive charge left behind. The speed of these electrons depends on their kinetic energy, so they will all travel at different speeds.
• In the photoelectric effect, the maximum kinetic energy of ejected electrons depends on the frequency of the incident radiation but not its intensity.
• Electrons have a wavelength given by de Broglie equation (λ = h/mv)
• In the case where the frequency of incident light is less than the threshold frequency, no electrons will be ejected because there is not enough energy available to overcome the binding force between the electrons and the metal atoms.
• Photon is a discrete packet of energy of electromagnetic radiation
• electrons absorb photons causing them to move to a higher energy level. the energy of the photon is equal to the difference in energy levels causing electrons to deexcite and emit a photon in all directions