BRAINCAKEQuantum Physics
Revision notes for Quantum Physics in Edexcel Physics (8PH0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Huygens PrincipleEvery point on a wavefront is a new source of circular waves.
- Light as a WaveInterference patterns are seen when light travels through two narrow slits in Young's double slit experiment.
- Light as a ParticleIn 1887 Hertz observed the photoelectric effect.
- The Energy of a PhotonFor electromagnetic radiation the energy of a photon is the frequency multiplied by the Planck constant h.
- Electrons as WavesElectrons behave as particles as a fixed number of electrons must be removed from an atom to make an ion.
- Photoelectric EffectIf ultraviolet light is directed at a negatively charged zinc plate the plate loses its charge.
- The Equation for the Photoelectric Effecthf = φ + ½mv2max The equation is based on the conservation of energy.
- Stopping PotentialWhen light with a frequency above the threshold frequency is shone on the cathode photoelectrons will be emitted and will travel across the gap to…
- Electron DiffractionThe strongest evidence that electrons can behave as waves comes from electron diffraction.
- DeBroglie WavelengthIn 1924 Louis de Broglie suggested that if light waves can behave as particles, then particles such as electrons should also behave as waves.
- Electron MicroscopesThe smallest detail a microscope can show, its resolution, is limited by diffraction.
- Electron Energy LevelsThe electrons in an atom can only have certain definite (discrete) energies.
- Excitation and De-excitationAn electron can move up to a higher energy level if it gains exactly the right amount of energy.
- Line SpectraWhen the light from a hot, low-pressure gas (for example in a discharge tube) is passed through a diffraction grating or a prism, it does not…
- Exam Question 1Question A laser pointer emits green light of wavelength 500 nm.
- Exam Question 2Question The work function of a metal is 2.30 eV.
- Exam Question 3Question Ultraviolet light of wavelength 250 nm is shone onto the metal cathode of a photocell.
- Exam Question 4Question In an electron diffraction tube, electrons are accelerated from rest through a potential difference of 150 V and then pass through a thin…
- Exam Question 5Question Some of the energy levels of a hydrogen atom are: n = 1: −13.6 eV, n = 2: −3.40 eV, n = 3: −1.51 eV.
- Exam Question 6Question A student measures the maximum kinetic energy Ek(max) of photoelectrons emitted from a metal for light of several different frequencies f…
- Exam Question 7Question (a) Describe one piece of evidence that electrons behave as particles and one piece of evidence that they behave as waves.
On the specification
- Topic 5: Waves and Particle Nature of Light