Quantum Physics Flashcards
What is the photoelectric effect?
When a certain frequency of light is shone onto different types of metals, the photons individually interact with the electrons in the metal causing them to gain enough energy to be released from the metal.
What is threshold frequency?
The minimum required frequency needed to be shone onto a metal for it to start emitting electrons.
What is the ’work function’?
The required energy needed to release an electron from a metal.
How does the work function change with the reactivity of a metal?
Generally, more reactive metals have a lower work function.
What is the equation for photon energy in photoelectric emission?
Photon energy = work function + kinetic energy of electron
What is stopping voltage?
The voltage necessary in a potential divider circuit to make the photocurrent zero
What is Plancks constant? (Value)
6.63x10^-34m
What is de broglie’s wavelength function?
Lambda = h (Planck constant) / p (momentum)
What is the equation for momentum? (Derived from the electron gun experiment)
P = sqrt( 2 x Ek x m )
What is the relation between wavelength and kinetic energy?
Lambda (wavelength) ∝ 1 / sqrt(Ek)
Def a photon
A photon is a quantum of EM radiation (like in cs with processes getting a quantum of runtime)
What is the equation for the energy of a photon?
E = (h (Planck constant) x c) / lambda (wavelength)
Or E= hc/lambda
What is the equation for the electron volt?
eV = (1/2)mv^2 where e is the elementary charge and V is voltage but v is velocity and m is mass
What is the name for an electron that has been released from a metal due to the photoelectric effect?
Photoelectrons
What two pieces of evidence show that light is a wave?
Light produces interference patterns and can also be diffracted which are only explained by light being a wave and following superposition.
