Quantum phenomena Flashcards
What are the four subsections in the topic of quantum phenomena?
photoelectricity, quantisation of electron energy levels, wave-particle duality and fluorescence.
What piece of equipment was used to observe the photoelectric effect?
A charged electroscope.
What was observed in the experiment using a charged electroscope?
Shining UV light on the plate discharged it but light of lower frequency didn’t discharge the plate.
What is Planck’s equation?
e = hf where e is energy, h is Planck’s constant and f is frequency.
What is DeBroglie’s equation?
λ = h/mv
What is the equation for energy including the work function?
e = ϕ+ E_k where ϕ is the work function and E_k is kinetic energy.
What is the equation for work function?
ϕ = hf_0 where ϕ is the work function, h is Planck’s constant and f_0 is the threshold frequency.
What is the threshold frequency?
The lowest frequency where electrons will be emitted.
What is the work function?
The minimum amount of energy requires to liberate an electron.
What effect will increasing the intensity of incident light have on emitted electrons?
More electrons will be emitted.
What effect will increasing the frequency of incident light have on emitted electrons?
The electrons will have more energy.
What experiment can be used to show that light is a wave?
Diffraction
What experiment can be used to show that light is a particle?
The photoelectric effect.
What is the only strange particle we are concerned with at A-level?
Kaon
What does the strong nuclear force act on?
Hadrons
What is the photoelectric effect and how does it occur?
High frequency light (usually in the UV range) is incident on the surface of a metal, free electrons on the surface absorb energy from the light which causes the bonds holding them to the metal to break which releases the electrons.
What is stopping potential?
The pd needed to stop the fastest moving electrons with maximum kinetic energy.
What is the equation for kinetic energy including stopping potential?
E_k(max) = eV_s where E_k(max) is the maximum kinetic energy (J), e is the charge on the electron (C) and V_s is the stopping potential (V).
What is an electronvolt defined as?
The kinetic energy carried by an electron after it has been accelerated from rest through a potential difference of 1 volt.
What happens when an electron moves down an energy level?
It emits a photon.
What happens when an electron moves up an energy level?
It absorbs a photon.
What is ionisation energy?
The energy required to remove an electron from an atom from the ground state (n = 1).
