Photoelectric Effect
Shine light of a chosen frequency onto a metal plate — adjust the frequency and the metal's work function to see whether an electron is ejected at all, and at what speed, exactly as Einstein's photon picture predicts.
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What you can adjust
- Light frequency
- 100 – 2000 THz
- Metal work function
- 1.5 – 6.5 eV
Higher frequency = higher-energy photons (violet/UV). Below the metal's threshold frequency, no electrons are ejected no matter how bright the light.
The minimum energy needed to free an electron from this metal — like sodium/cesium (~2.1-2.3 eV) at the low end up to platinum (~6.35 eV) at the high end.
About this simulation
What it shows
Light of a chosen frequency hits a metal plate. If each photon carries enough energy, an electron is ejected and its speed is shown; if not, nothing is emitted.
The key idea
Light arrives in packets (photons) with energy E = hf. An electron is freed only if hf is bigger than the metal's work function, and the leftover energy becomes its kinetic energy. Below the threshold frequency no electrons escape, however bright the light.
Try this
At 700 THz (photons of about 2.9 eV), raise Metal work function from 2.3 eV to 3.5 eV: the photons no longer have enough energy and no electron is ejected.