What this calculator does
Photoelectric Effect works out kinetic energy and stopping voltage of electrons ejected from a metal by light. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaEphoton = h·c/λ = W0 + KEmax; Vstop = KEmax/e
The inputs explained
| Field | What to enter |
|---|---|
| Wavelength of incident light (λ) (nm) | A number, measured in nm. Starts at 400. |
| Work function of the metal (W0) (eV) | A number, measured in eV. Starts at 2.3. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with wavelength of incident light (λ)
Every other input is held at the calculator’s starting values while wavelength of incident light (λ) varies. Select any row to load that scenario into the calculator.
How the answer changes with wavelength of incident light (λ)
| Wavelength of incident light (λ) (nm) | Maximum kinetic energy (KEmax) | Stopping voltage (Vstop) | Photon energy |
|---|---|---|---|
| 200 | 3.899 eV | 3.899 V | 6.199 eV |
| 300 | 1.833 eV | 1.833 V | 4.133 eV |
| 400 | 0.7996 eV | 0.7996 V | 3.100 eV |
| 600 | No emission, photon energy is below the metal's work function | 2.066 eV | 539.1 nm |
| 800 | No emission, photon energy is below the metal's work function | 1.550 eV | 539.1 nm |
| 1,200 | No emission, photon energy is below the metal's work function | 1.033 eV | 539.1 nm |