Photoelectric Effect Calculator
From Wavelength
Calculate photoelectron kinetic energy from incident light wavelength and work function
From Frequency
Calculate photoelectric parameters from incident frequency
Find Work Function
Determine the work function from stopping voltage and wavelength
Formula
KE_max = hf - φ = hc/λ - φ | V_s = KE_max / e | f₀ = φ/h | λ₀ = hc/φ
Frequently Asked Questions
What is the photoelectric effect?
The photoelectric effect is the emission of electrons from a surface when light shines on it. Einstein explained it in 1905: a photon of energy E = hf ejects an electron only if E exceeds the work function φ. The maximum kinetic energy is KE_max = hf - φ.
What is the work function?
The work function (φ) is the minimum energy needed to remove an electron from a material's surface. Common values: Cesium 2.1 eV, Sodium 2.3 eV, Zinc 4.3 eV, Platinum 5.6 eV. Photons with energy below φ cannot eject electrons regardless of intensity.
What is stopping voltage?
Stopping voltage (V_s) is the potential difference needed to stop the most energetic photoelectrons. It directly gives the maximum kinetic energy: KE_max = eV_s. It is independent of light intensity — only wavelength/frequency matters.
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