Photoelectric Effect Calculator — KE = E − Φ

Einstein's photoelectric equation: a photon's energy minus the metal's work function becomes the electron's kinetic energy. Below the threshold frequency, nothing is emitted — no matter how bright the light.

Photoelectric Effect Calculator — KE = E − Φ

$KE_{max} = E_{photon} - \Phi$

Solve for

Photon energy (E)

Unit

Work function (Φ)

Unit

Result unit

How to interpret the result

400 nm violet light (3.10 eV) on sodium (Φ = 2.75 eV) ejects electrons with 0.35 eV — but red light, however intense, ejects nothing.

Assumptions

Photon energy must exceed the work function
Single-photon absorption