How to Use Photoelectric Effect Calculator
The Photoelectric Effect Calculator takes a photon energy (or wavelength/frequency) and a metal work function, and returns the maximum kinetic energy, stopping voltage, and threshold frequency.
- Enter the photon - Choose wavelength (nm), frequency (THz, PHz), or energy (eV) as your input. The Photoelectric Effect Calculator converts to energy internally.
- Enter the work function - In eV. Common reference values: Cs 2.1 eV, K 2.3 eV, Na 2.36 eV, Al 4.1 eV, Cu 4.7 eV, Au 5.1 eV, Pt 5.7 eV. Use your material’s measured value for the most accurate result.
- Read the result - The Photoelectric Effect Calculator shows KE_max, stopping voltage V_stop, and threshold frequency f_th. If photon energy < work function, the calculator reports zero KE and displays the threshold.
- Explore the threshold - Increase the photon energy gradually from below φ to above it to visualize the sharp onset of photoemission — a key quantum-physics demonstration.
Formula & Theory - Photoelectric Effect Calculator
The Photoelectric Effect Calculator uses Einstein’s photoelectric equation:
KE_max = h · f − φ (if h f > φ)
V_stop = KE_max / e
f_th = φ / h
λ_th = h c / φ| Symbol | Meaning |
|---|---|
| h | Planck constant |
| f | Photon frequency |
| φ | Material work function |
| e | Elementary charge |
| KE_max | Maximum electron kinetic energy |
Work Function Reference Table
| Metal | Work function (eV) | Threshold wavelength (nm) |
|---|---|---|
| Cs | 2.10 | 591 (visible) |
| K | 2.30 | 539 (visible) |
| Na | 2.36 | 526 (visible) |
| Al | 4.10 | 302 (UV) |
| Cu | 4.70 | 264 (UV) |
| Pt | 5.65 | 220 (deep UV) |
Assumptions and Limits
Einstein’s equation assumes a single photon ejects a single electron, no multi-photon processes, and a clean surface. For real samples, expect corrections from surface dipoles, contamination layers, and contact potentials.
Use Cases for Photoelectric Effect Calculator
The Photoelectric Effect Calculator is useful when you need a quick, transparent calculation for quantum and surface physics:
- Photocathode design - Match the emission threshold wavelength to a desired illumination source (e.g., cesium photocathodes for visible-light detectors).
- Spectroscopy - Predict stopping voltages in retarding-field photoemission experiments (UPS / XPS) to calibrate energy analyzers.
- Quantum mechanics teaching - Demonstrate why photon energy, not light intensity, controls electron emission — the cornerstone of Einstein’s 1905 paper.
- Solar cell context - Compare metal work functions with photon energies in the visible band to understand why certain metals show strong photoemission under sunlight.
- Security and sensing - Estimate detection thresholds for UV-photodiode sensors used in flame detection and ozone measurement.
- Materials screening - Quickly rank candidate cathode materials by threshold wavelength to select the best match for a given light source.
For full angle-resolved photoemission (ARPES) interpretation or multi-photon processes, use a dedicated code. The Photoelectric Effect Calculator delivers the fast, transparent single-photon answer that is the starting point for all photoemission analysis.