Physics · Chemistry · Virtual lab
Photoelectric Effect
Explore how light frequency, intensity, and voltage affect electron emission from metal surfaces.
Background
The photoelectric effect is the emission of electrons from a metal surface when light of sufficient frequency shines on it. Albert Einstein explained this phenomenon in 1905 by proposing that light consists of discrete packets of energy called photons, each carrying energy E = hf, where h is Planck's constant and f is the frequency.
If a photon's energy exceeds the metal's work function (the minimum energy needed to free an electron), an electron is ejected. Increasing the light intensity increases the number of emitted electrons but not their kinetic energy; only increasing the frequency raises the maximum kinetic energy.
In this virtual lab you vary the light frequency, intensity, and applied voltage on different metal surfaces, observe the resulting photocurrent, and verify Einstein's photoelectric equation: KE_max = hf − φ.
What you will learn
- Understand the relationship between light frequency and electron emission
- Determine the threshold frequency for different metals
- Measure stopping potential and calculate maximum kinetic energy
- Verify Einstein's photoelectric equation experimentally
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