Photoelectric Effect Calculator

Your details

Choose whether to enter the incident light as a wavelength or as a frequency.
Wavelength of the incident photon in nanometres. Visible light spans about 380-700 nm; UV is below 380 nm.
nm
Select a preset metal to auto-fill its work function, or choose 'Custom' to enter your own value.
Photon energyEjection occurs
4.1328eV

Energy carried by one photon of the incident light (E = hf = hc/lambda)

Photon energy0J
Work function2.36eV
Max kinetic energy (Kmax)1.7728eV
Stopping potential (Vs)1.7728V
Threshold frequency (f0)570.6455THz
Threshold wavelength (lambda0)525.36nm
Max electron speed789,690m/s
Ejection statusElectrons are ejected (photon energy exceeds work function)
Photon energy (eV)4.1328
Work function (eV)2.36
Kmax (eV)1.7728

Photoejection confirmed: Kmax = 1.7728 eV

  • The incident photon carries 4.1328 eV of energy. The work function of Sodium is 2.3600 eV.
  • Ejection occurs. The fastest photoelectron carries 1.7728 eV of kinetic energy, and it would take 1.7728 V to bring it to rest.
  • Any photon with a wavelength shorter than 525.4 nm (the threshold wavelength) will eject electrons from this material.
  • This result follows from Einstein's 1905 explanation: the photoelectric effect depends on photon frequency, not intensity.

Next stepTry increasing the wavelength toward 525 nm to watch the kinetic energy drop to zero at the threshold.

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