Physics
Photoelectric Effect
KE = max(0, hν − φ)

No electrons are ejected until the light exceeds the threshold frequency φ/h; above it the ejected kinetic energy climbs linearly with frequency.
Computed & rendered in pure C# on the frozen OnlyCSharp 1.8 library — animation baked to GIF with the library's own
Gif encoder (no GPU, no ffmpeg, no external packages).