Chapter 12.1 Flashcards
Quantum
A bundle of light
Formulas for momentum of photons
p = E/c = hf/c = h/λ
Photoelectric effect
The phenomenon in which light incident on a metallic surface causes electrons to be emitted from the surface
Photo-surface
The metallic surface that light is incident on
Stopping voltage
The voltage at which the current in a device investigating the photoelectric effect becomes zero
Why is the stopping voltage in the photoelectric effect significant?
Gives the maximum kinetic energy of emitted electrons, eVs
True or false? Stopping voltage is dependent of the intensity of the light source
False. Stopping voltage is independent of intensity
Four observations from photoelectric effect experiment
- The intensity of light does not affect the energy of the emitted electrons
- The electron energy depends on the frequency of the incident light
- There is a certain minimum frequency below which no electrons are emitted
- Electrons are emitted with no time delay
Quanta
Bundles of energy and momentum
Formula for energy of a quantum
E = hf
h = 6.63 x 10^(-34)
Work function
The amount of energy an electron spends to free itself from the pull of the nuclei of the atoms of a photo-surface
Formula for maximum kinetic energy of an electron emitted from a photo-surface
Emax = hf - Φ
Pair annihilation
The process where a particle collides with an anti-particle and forms two photons
Pair creation
When a single photon is produced in the presence of a nucleus from pair annihilation
Formula for longest wavelength of particles emitted from particle annihilation
λ = (hc)/(mc^2)
Angular momentum formula
mvr = (nh)/(2π)
Formula for electron energy in a hydrogen atom
E = -13.6/n^2 eV
Wavefunction
The wave in Schrödinger’s theory, which is a function of position and time
Heisenberg uncertainty principle
It is not possible to measure simultaneously the position and momentum of a particle with indefinite precision
Heisenberg formula for finding uncertainty in position and momentum
∆x∆p ≥ h/4π
Heisenberg formula for finding uncertainty of energy and time
∆E∆t ≥ h/4π
Three factors that affect probability of tunneling
Mass of particle
Width of barrier
∆E between barrier and particle
