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Photoelectric Effect Calculator

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What is the photoelectric effect?Photoelectric effect definitionPhotoelectric sensor

The photoelectric effect calculator will give you an insight into the principles of the photoelectric effect, which Einstein explained in 1905. It was a significant step in the development of quantum physics as we know it today.

Read on if you want to learn what is the photoelectric effect and how you can describe it using the photoelectric effect definition. You will see that this quantum phenomenon finds an application in our everyday life, among others, in photoelectric sensors that detect and determine the intensity of the incident light (with the photoelectric effect equation, you can check if they will work at all in the sunlight).

What is the photoelectric effect?

Everything in nature consists of atoms that are built of a nucleus and electrons orbiting around the nucleus. Check out our Bohr model calculator to find more information about the structure of an atom.

The photoelectric effect is a quantum phenomenon in which electrons are emitted from the surface of a material under the influence of incident light. Such photoemission can occur for any material, but it is most observable in metals.

But why is there a photoelectric effect at all? Light rays consist of elementary particles – photons – with definite energy. On the other hand, every electron is bound to the nucleus with specific binding energy (you can quickly estimate this energy for hydrogen – see the hydrogen energy levels calculator).

Now, if a photon collides with an electron and the energy of the photon exceeds the electron's binding energy, it can escape with some kinetic energy from the nucleus, giving rise to the photoelectric effect.

🙋 Did you know that atoms or molecules can also absorb two photons simultaneously? The phenomenon is called two-photon absorption.

Photoelectric effect definition

Einstein proposed an explanation of the photoelectric effect using the concept that light consists of tiny packets of energy known as photons. Our photoelectric effect calculator uses the following photoelectric effect definition:

Kmax=h(ff0),K_{\rm{max}} = h(f - f_0),


  • KmaxK_{\rm{max}} – Maximum kinetic energy of an ejected electron;
  • ff – Frequency of the incident photon;
  • f0f_0 – Threshold frequency (corresponding to the binding energy) of a certain material; and
  • hh – Planck constant: h=6.626×1034 Jsh = 6.626 \times 10^{-34}\ \rm{J \cdot s}.

You can see from the photoelectric equation that the condition f>f0f \gt f_0 is necessary for the photoelectric effect to occur (because kinetic energy is positive). The quantity ϕ=hf0\phi = hf_0 is called the work function (expressed in units of energy) and corresponds to the threshold frequency.

In our photoelectric effect calculator, the energy of the incident photon and work function are expressed as frequencies. Click on the Additional data drop-down list if you want to use wavelength or just energy. Check our photon energy calculator to find the relation between the frequency, wavelength, and energy of phonon.

Photoelectric sensor

The description of the photoelectric effect sounds very theoretical, but it finds many practical applications. Photoelectric cells are, for example, used to detect light (in photoelectric sensors) or to gather the resulting current of electrons (in solar cells) to produce electricity. Other applications include:

  • Imaging technology (digital cameras);
  • Photomultiplier (amplifies current from detected photon); and
  • Chemical analysis of a material.

Incident light

Work function

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