Photoelectric Effect Calculator
Compute the maximum kinetic energy of photoelectrons, the stopping voltage, and the threshold frequency and wavelength from the light frequency (or wavelength) and the metal work function.
Input type
Hz
eV
Electrons are emitted
- 1
Photon energy E = h × f
6.626×10⁻³⁴ × 1.200e+15 = 4,963 eVDivided by the elementary charge to convert J → eV. - 2
Work function φ
2,3 eV - 3
Max KE = E_photon − φ
4,963 − 2,3 = 2,663 eV
Miten tämä laskin toimii?
The maximum kinetic energy of a photoelectron is KE_max = h·f − φ. Convert the work function from eV to joules, use f = c/λ if given a wavelength, and if h·f is below φ no electrons escape. The stopping voltage is V0 = KE_max/e, the threshold frequency is f0 = φ/h, and the threshold wavelength is λ0 = c/f0.
Kaava
How this is calculated
Einstein's photoelectric equation states that the maximum kinetic energy of an emitted electron equals the photon energy h·f minus the work function φ, the minimum energy needed to liberate an electron from the metal surface. Here h is Planck's constant (6.62607015e-34 J·s). You can supply the light frequency f directly in hertz, or a wavelength λ in nanometres, in which case f = c/λ with c = 299,792,458 m/s. The work function is entered in electron-volts and converted to joules by multiplying by the elementary charge e = 1.602176634e-19 C.
If the photon energy h·f is less than φ, no electrons are emitted regardless of light intensity and the kinetic energy is reported as zero. When emission occurs, the stopping voltage V0 is the potential that just halts the fastest electrons: V0 = KE_max / e, which is numerically equal to KE_max expressed in electron-volts. The threshold frequency f0 = φ/h is the lowest frequency that can cause emission, and the corresponding threshold wavelength is λ0 = c/f0.
Results are shown in both electron-volts and joules. The model assumes single-photon absorption, a clean uniform surface with a single work function, and neglects thermal energy of electrons and any contact-potential corrections. All inputs must be positive; non-positive frequency, wavelength, or work function values are rejected.
Usein kysytyt kysymykset
No electrons are emitted no matter how intense the light, because each photon carries h·f of energy and a single photon cannot supply enough to overcome the work function. The calculator reports zero kinetic energy and zero stopping voltage in this case.
The stopping voltage V0 satisfies e·V0 = KE_max, so V0 = KE_max/e. Since one electron-volt is defined as e times one volt, KE_max measured in eV gives exactly the same number as V0 measured in volts.
It is the longest wavelength (lowest frequency) of light that can still eject electrons: λ0 = c/f0 = h·c/φ. Light with a longer wavelength than λ0 has too little energy per photon to cause emission.
Tunnetaan myös nimellä
TG we-Calculate Editorial Team. (2026). Photoelectric Effect Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/fi/calculator/photoelectric-effect-calculator
TG we-Calculate Editorial Team. "Photoelectric Effect Calculator." TG we-Calculate. 2026. https://we-calculate.com/fi/calculator/photoelectric-effect-calculator.
TG we-Calculate Editorial Team, "Photoelectric Effect Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/fi/calculator/photoelectric-effect-calculator
@misc{wecalculate_photoelectric_effect_calculator, title = {Photoelectric Effect Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/fi/calculator/photoelectric-effect-calculator}}, year = {2026}, note = {TG we-Calculate} }
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