4.5 - Quantum Physics Flashcards
What is a Quantum?
A small discrete unit of energy
What is a Photon?
A quantum associated with electromagnetic radiation
What is the Planck Constant?
A value for which photon energies are always emitted in multiples of. Measured in Js
What is an Electronvolt?
The kinetic energy gained by an electron when it is accelerated through a potential difference of 1 volt
What is the Threshold Frequency?
The lowest frequency of radiation that will result in the emission of electron from a particular metal surface. For most metals, this frequency occurs in the UV region or the EM spectrum
What is the Work Function?
The minimum energy required to release an electron from a metals surface, overcoming the electrostatic attraction between the electron and the positive metal ions
What is the photoelectric effect?
When electromagnetic radiation of a particular frequency is shone on the surface of a metal and electrons are emitted from its surface
What are the electrons released due to the photoelectric effect called?
Photoelectrons
How do you find the maximum kinetic energy of emitted photoelectrons?
The charge of an electron x stopping potential (voltage at which photoelectrons stop being emitted)
What is the number of emitted photoelectrons directly proportional to?
The intensity of the incident radiation (provided that the radiation is of a single frequency and is above the threshold frequency)
What is the kinetic energy of the emitted photoelectrons affected by?
The frequency of the incident photons
