Calculadora de Efeito Fotoelétrico
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
E_k = h·f − φ
About this calculator
The Photoelectric Effect Calculator determines the maximum kinetic energy of electrons emitted from a metal surface when illuminated by light of a given frequency. The calculation is based on Einstein's photoelectric equation: E_k = h·f − φ, where h is Planck's constant, f is the frequency of incident light, and φ is the work function of the metal. The tool allows users to input frequency and work function values to obtain the maximum kinetic energy of photoelectrons.
Operation is straightforward: the user provides the frequency of electromagnetic radiation (in hertz) and the work function of the material (in electron-volts). The calculator converts Planck's constant to eV·s and performs the subtraction, returning the result in electron-volts. If the photon energy is less than the work function, no electrons are emitted and the result is zero. The tool also indicates whether photoelectron emission occurs.
Use this calculator in educational contexts, such as modern physics and quantum mechanics studies, or in labs to verify experimental results. It is useful for understanding the relationship between light frequency and emitted electron energy, as well as illustrating the concept of threshold frequency. It can also be applied in engineering projects involving photocells or light sensors.
Cautions: ensure you use the correct frequency of incident light (not the wavelength directly) and the appropriate work function for the specific metal. The formula assumes that the photon's energy is fully transferred to a single electron, disregarding losses from collisions or thermal effects. Additionally, the calculator provides the maximum kinetic energy; electrons may have lower energies due to internal interactions.
Frequently asked questions
What does it mean if the result is zero?
If the result is zero, it means the photon energy is equal to or less than the work function, so no electrons are emitted. This indicates the light frequency is at or below the threshold.
Can I use wavelength instead of frequency?
The calculator expects frequency in hertz. If you have wavelength, use the relation c = λ·f (c is speed of light) to convert to frequency before inputting.
What is the unit of the calculated kinetic energy?
The result is given in electron-volts (eV), which is the common unit for atomic-scale energies.
Does the calculator consider the temperature of the metal?
No, Einstein's photoelectric equation disregards thermal effects. For metals at high temperatures, thermionic emission may occur, but that is not covered by this tool.
What is work function and how do I find its value for a metal?
The work function is the minimum energy needed to remove an electron from the metal surface. Typical values can be found in physics tables; examples: sodium ~2.3 eV, aluminum ~4.1 eV.