The photoelectric effect is key when producing photovoltaic solar energy, for example.
Photoelectric effect is a concept that was consolidated from a discovery made in 1887 by a German physicist named Heinrich Rudolf Hertz . This expert warned that when ultraviolet light shines on a charged element, it tends to easily lose its charge. Their observation showed that, with such lighting, the distance of the arc that extends between a pair of electrodes that are connected to a high voltage source is greater than that evident when the object is exposed to darkness.
It was Albert Einstein , in any case, who, motivated by the constructive work of Max Planck – a key figure who provided a solid and coherent conceptual framework to conceive in a simple way the photoelectric effect and understand the quantization of energy without major complications – was in charge of offering a theoretical explanation in this regard. Thanks to his valuable contributions on this topic, in 1921 the Nobel Prize in Physics was awarded to the also promoter of the famous theory of relativity (from which the equation E=mc^2 is derived, the ideal formula to establish what energy presents a body in a state of rest by multiplying the apparent relativistic mass by the speed of light).
Before focusing on the characteristics, relevance and other issues linked to this effect , it is enriching to know (or remember) that, in the field of physics , the notion of photoelectric is used to describe the electrical phenomena that occur. as a consequence of the influence of either visible light or some other electromagnetic radiation with a similar wavelength .
Characteristics of the photoelectric effect
There are several characteristics that trace the unique essence of the photoelectric effect . Beyond being aware of these particularities, it is also necessary to educate yourself about what Einstein's equation for the photoelectric effect is like (a structure where Planck's constant , the work function , the frequency associated with the incident radiation - the which is connected to the wavelength through the speed of light – and the highest kinetic energy observed experimentally in electrons ).
It should not be overlooked that the human eye cannot observe quantization : that is why we do not detect dark spaces between light sectors but rather we perceive light continuously (without interruptions). When carrying out tests inspired by the photoelectric effect , an absence of delay or delay is even noted between the period in which light first hits a metal and the moment in which the electron appears after the absorption of energy. According to the model proposed by Einstein , light energy becomes concentrated in photons (that is, in quanta of light ) and it is not necessary to wait time for the accumulation of energy in the electrons to occur, since this transfer to the photoelectrons It is immediate, just as happens with their escape to the surface.
In recognition of his findings and explanations of the photoelectric effect, Albert Einstein was awarded a Nobel Prize in Physics.
Importance
As determined by specialists who studied what it involves, how it develops and how the photoelectric effect is translated into practice, this phenomenon marks that one photon (or more) is in a position to transfer energy to electrons.
Every electron is capable of being emitted based on the photoelectric effect , although this only happens with those that require a lower percentage of energy to end up ejected in relation to their orbit. It has been proven that the energy obtained by each emitted electron depends on the energy of the photons and not on the intensity of the light, which does have an impact on the electric current produced.
It is interesting to highlight that based on knowledge about the photoelectric effect, it was possible to begin to clearly make visible the wave-particle duality so typical of the field of quantum mechanics . With the passage of time, mysteries were revealed and details were added about the extraordinary phenomenon that, without a doubt, has marked a before and after in human understanding of matter and light.
Sometimes the photoelectric effect is associated with different interactions between matter and light, as occurs with the photovoltaic effect and photoconductivity.
Examples of photoelectric effect
By investigating multiple issues in everyday life, different examples of practical application or use of the photoelectric effect emerge. This comes into play, to indicate a specific case, in photoelectron spectroscopy techniques (also called photoemission spectroscopy ).
The phenomenon is considered, in the same way, to transform energy from the sun into electrical energy through a photovoltaic cell (sometimes cataloged as a photoelectric cell ).
If the photoelectric effect had not been detected, it would be difficult to manufacture devices or apparatus intended to convert light into electrical energy . Nor could modern physics have evolved that much. The combination of theoretical material and experiments facilitated by cutting-edge technology have paved the way for solar cells , photodiodes and other useful elements to automate industrial processes, the operation of optical scanners, etc.