What a photon is, the four photoelectric observations wave theory cannot explain, Einstein's KE_max = hν − φ, and the two graphs the paper asks you to read.
Unit 6 carries 12 of the 50 physics marks — the heaviest unit in the subject — and with seven chapters sharing them, this one averages a little under two (MEC publishes weights by unit, not by chapter). It is the chapter where light stops being a wave, and the equation written here is reused in the next chapter for de Broglie waves and for the X-ray cut-off wavelength.
The MEC scope line is: Concept, laws and calculations related to photons and the photoelectric effect. That single point is the heading below, with subsections inside it.
Three ways it is asked: recall (the four laws of photoelectric emission, what a photon's rest mass is, who got which Nobel Prize, where photocells are used); understanding (why raising the intensity does not raise the electron energy, why the emission is instantaneous, what a graph of stopping potential against frequency tells you); application (a KE_max or a stopping potential from a wavelength and a work function, a threshold wavelength, the number of photons a lamp emits per second, the slope of a graph).
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