Photoelectric Effect Simulator
Discover Einstein's photoelectric effect by blasting electrons off metal surfaces.
About this simulation
- What
- An interactive Physics simulation of Photoelectric Effect Simulator.
- Who
- Designed for AP, IB, and A‑Level Physics students.
- How
- Runs in any modern browser — drag, adjust, and explore in real time.
Updated 2026-03-18
Key Concepts
Threshold Frequency
No electrons are emitted unless the incident light's frequency is higher than a specific threshold characteristic of the metal.
$E = h\nu - W$
Einstein's equation: The kinetic energy of the escaping electron is the photon's energy minus the metal's work function ($W$).
Stopping Voltage
Subjecting the electrons to a reverse voltage can stop even the fastest ones, giving us a direct measure of their maximum kinetic energy.
Proving Light is a Particle
Before 1905, physics believed light was strictly a continuous wave. But the photoelectric effect threw a wrench into classical physics: dim blue light could knock electrons off a metal plate instantly, while blindingly bright red light couldn't knock off a single one.
Albert Einstein solved the mystery by proposing that light comes in discrete packets called 'photons'. An electron can only absorb ONE photon at a time. If that single photon doesn't have enough energy (i.e. its wavelength is too long), the electron can't escape the metal's grip (the Work Function $W$).
Use this simulator to test different metals. Find the exact wavelength where electron emission begins, and use the reverse voltage slider to find the 'Stopping Voltage' that halts the electron flow completely.