Photoelectric Effect Rechner — Formel
## Photoelectric Effect
Einstein explained that light consists of photons, each carrying energy E = hf. When a photon hits a metal surface, it can eject an electron if its energy exceeds the work function.
### Formula
**KE_max = hf - phi = (hc/lambda) - phi**
where phi is the work function (minimum energy to free an electron). The threshold wavelength is **lambda_0 = hc/phi**.
Einstein explained that light consists of photons, each carrying energy E = hf. When a photon hits a metal surface, it can eject an electron if its energy exceeds the work function.
### Formula
**KE_max = hf - phi = (hc/lambda) - phi**
where phi is the work function (minimum energy to free an electron). The threshold wavelength is **lambda_0 = hc/phi**.
Lösungsbeispiel
UV light at 250 nm hitting sodium (work function = 2.3 eV).
- E_photon = hc/lambda = (6.626e-34 * 3e8) / (250e-9)
- E_photon = 7.95e-19 J = 4.96 eV
- KE_max = E_photon - phi = 4.96 - 2.3
- KE_max = 2.66 eV
- Threshold: lambda_0 = hc/phi = 1240/2.3 = 539.1 nm