The photoelectric effect
- Created by: Lucy
- Created on: 13-11-12 18:44
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- The Photoelectric effect
- If you shine light of a high enough frequency onto the surface of a metal, it will emit electrons.
- 1) Free electrons on the surface of the metal absorb energy from the light, making them vibrate.
- 2) If an electron absorbs enough energy, the bonds holding it to the metal break and the electron is released.
- 3) This is called the photoelectric effect and the electrons emitted are called phoyoelectrons.
- Before an electron can leave the surface of a metal,it needs enough energy to break the bonds holding it there, this energy is called the work function energy (symbol ?, (phi))
- For electrons to be released, hf > ?
- Therefore f= ?/h
- Maximum kinetic energy is given by: hf=? + ½mvmax²
- The kinetic energy it will be carrying when it leaves the metal if hf minus any energy it's lost on the way out
- The kinetic energy of the the electrons is independent of the intensity, because they can only absorb one photon at a time.
- For electrons to be released, hf > ?
- The maximum kinetic energy increases with the frequency of radiation, but is unaffected by the intensity of the radiation.
- The number of photoelectrons emitted per second is proportional to the intensity of the of the radiation.
- If you shine light of a high enough frequency onto the surface of a metal, it will emit electrons.
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