Convert work function into threshold frequency, wavelength, photon energy, kinetic energy, and stopping potential with clear photoelectric-effect steps and flexible scientific units.
The threshold frequency is the minimum photon frequency for emission.
When incident frequency exceeds it, electrons gain kinetic energy.
The photoelectric effect links photon energy with electron emission. A surface releases electrons only above a minimum photon energy. That minimum energy equals the material work function. The work function depends on the material and its surface. Oxides, contamination, and crystal orientation can change measured values.
Threshold frequency describes the lowest useful incident light frequency. It follows directly from Einstein’s photoelectric equation. Divide the work function in joules by Planck’s constant. The resulting frequency is measured in hertz. A related threshold wavelength comes from light speed. Longer wavelengths have lower photon energies. Therefore, wavelengths above the threshold generally cannot eject electrons.
Work functions are often reported in electron-volts. One electron-volt equals the energy gained by one electron across one volt. This calculator converts electron-volts into joules automatically. It also supports joules, ergs, and kilojoules per mole. Molar energy is converted to energy per particle using Avogadro’s constant.
Threshold calculations become more useful with an incident photon value. Enter frequency directly, or enter a wavelength instead. The calculator converts wavelength into frequency using light speed. It then compares photon energy against the work function. If photon energy is too small, electron emission does not occur.
When the photon energy is high enough, excess energy appears as kinetic energy. The maximum kinetic energy follows Kmax = hf − φ. Dividing that energy by elementary charge gives stopping potential. This voltage can stop the fastest emitted photoelectrons.
Use material presets as practical reference values, not absolute constants. Real surfaces can differ from textbook values. Experimental work should use a measured work function whenever available. Keep units consistent and review the calculation steps. Scientific notation is especially useful for optical frequencies. Exported results can support worksheets, reports, laboratory notes, and classroom examples.
| Material | Approx. Work Function (eV) | Approx. Threshold Frequency (THz) | Approx. Threshold Wavelength (nm) |
|---|---|---|---|
| Cesium | 2.14 | 517 | 580 |
| Potassium | 2.30 | 556 | 539 |
| Calcium | 2.90 | 701 | 428 |
| Aluminum | 4.08 | 987 | 304 |
| Copper | 4.70 | 1136 | 264 |
| Platinum | 5.65 | 1366 | 219 |
It is the minimum photon frequency that can eject electrons.
Divide the material work function by Planck’s constant.
Yes. The calculator converts electron-volts into joules automatically.
It is the longest wavelength that still reaches threshold energy.
Photoelectric emission does not occur in the ideal model.
It is the voltage needed to stop maximum-energy photoelectrons.
Surface condition, crystal orientation, and contamination change measured values.
Yes. Switch the constants selector to custom values.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.