01
What you will learn
- One photon carries energy hf.
- Emission begins only above the metal’s threshold frequency.
- Frequency changes maximum electron energy; intensity changes the emission rate.
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Quantum · reward round
Photon Foundry
Tune the light, beat the work function, eject the electrons. Each photon carries E = hf; the metal’s wall costs φ; whatever is left, KE = hf − φ, throws the electron toward the collector gate. The intensity lever only changes how many electrons fly — never how far. Below the threshold frequency it changes nothing at all.
Score0best 0 · streak 0× · centre of the gate = +2
KE = hf − φ1.08eVhf 2.98 eV − φ 1.9 eV · visible
Caesium0/3collected6 shots left · level 1/5 · gate ≈ 2.2 eV
Score 0 · level 1/5 · Caesium first — the wall is its work function
How the physics works
Each photon carries E = hf — about 4.1 eV per petahertz of frequency. An electron absorbs one photon or none: if hf is less than the metal’s work function φ, the electron stays put, which is why the infrared end of the dial does nothing on every metal no matter where the intensity lever sits. There is no saving up between photons.
Above threshold, the surplus KE = hf − φ becomes launch energy. The game integrates each electron’s flight step by step — the dashed ghost line runs through the very same integrator — so the landing distance is a direct readout of kinetic energy, exactly the quantity a stopping potential measures in the real experiment: the collector gate’s eV label is the stopping-potential value that would just turn those electrons back.
The intensity lever multiplies the number of electrons per burst and nothing else: five dim-beam electrons land exactly as far as one, because photon count and photon energy are independent dials. Einstein’s 1905 argument, playable: frequency sets the physics, intensity sets the statistics.
Game 25 · Quantum learning guide
Turn the playthrough into a physics lesson.
Learning objectiveSelect light frequency and intensity to release photoelectrons with the kinetic energy needed to reach a collector gate.
02
How to play
- Read the metal’s work function and the collector’s energy gate.
- Set beam frequency and intensity with the game controls.
- Fire the beam, inspect electron energy, and tune the frequency to reach the target.
03
Quick classroom check
Why can very intense light below the threshold frequency still fail to emit photoelectrons?
Suitable forUpper-secondary physics · photons and the photoelectric effect
Continue this topic
Move from play to explanation and exam-style practice.
Teachers can share the page link with a class. The game is free and does not require an account.