Planck's constant, whose value is approximately 6.626 070 15 × 10-34 joules per second, is identified by the letter h (lowercase).
Planck's constant is a value of great relevance within quantum mechanics . This is an important discovery made by the German-born physicist Max Karl Ernst Ludwig Planck ; hence the name chosen to identify this physical constant, which is expressed by the letter h and which is calculated, by approximation, at 6.62607015×10^−34 joules per second.
As soon as it was officially announced, this resource was used to determine the amount of energy of the photons , presenting it as a constant of proportionality that involves the own energy of a photon and the frequency evidenced by the electromagnetic wave linked to it. It also intervenes in the equation that connects the linear momentum of a given particle with its wave-particle duality .
As time went by, Planck 's contributions served to demonstrate that an electron can simultaneously be a wave and a particle and that light waves can behave like streams of particles .
History and discovery of Planck's constant
By searching for data linked to the history and discovery of Planck's constant , the so-called law of energy distribution of the normal spectrum becomes visible. In this framework, the notion of a black body gained relevance and the challenge that Max Planck posed in relation to the considered ultraviolet catastrophe after noticing that the results in the experimental phase had discrepancies with respect to those accumulated when applying traditional laws of physics. The expert tested numbers and calculations associated with the amount of energy that a black body is capable of emitting and absorbing, approaching it as a series of discrete packages. Thus he was able to determine that radiation is neither emitted nor absorbed continuously but in very small quantities of energy (to the point of being indivisible) called quanta .
After the impulse of quantum mechanics (a field in which the value of each physical magnitude intended to describe the state of motion of the particles is not known exactly because they lack a precise trajectory), the way of understanding was transformed, to atomic scale, natural phenomena. Albert Einstein , for his part, directed efforts to explain the photoelectric effect . Through Bohr's atomic model and postulates related to it, there was also a revolution around the atom and the processes of emission and ability to absorb light, in a discrete way, by matter . Planck's theory , as it emerges from practice, is also linked to Heinsenberg's uncertainty principle .
It cannot be overlooked that Planck's research on black bodies and the contributions he made to theoretical physics Einstein (who gave birth to the theory of general relativity and focused on the photoelectric effect , for example) They allowed the American physicist Arthur Compton to demonstrate the quantum essence of light. This is how dispersion or the Compton effect arose, characterized by the increase in the wavelength of a photon when it collides with a free electron , a scenario in which it ends up losing a portion of its energy. It has been found that, in this context, the scattering angle is key to the wavelength or frequency of the radiation that has been scattered.
Within the scope of quantum mechanics, the Planck time constitutes the smallest unit that a measurement can be made, taking into account that this expression refers to the time it takes for a photon to travel at the speed of light and traverse an equivalent distance. to the Planck length.
Applications and associated phenomena
Planck's constant has multiple applications and associated phenomena. On the one hand, it is used by those who work at the atomic scale in matters related to Physics to, for example, determine what energy a photon has, within the visible spectrum .
Using Planck's law , on the other hand, it is possible to specify how much electromagnetic radiation a black body emits, in thermal equilibrium and at a specific temperature. It should be noted that the energy released by one of these ideal physical bodies (which are non-reflective and opaque) is identified as black body radiation .
Within quantum mechanics , in addition, it is possible to appreciate a quantum phenomenon that puts at the center of the scene a particle that, upon penetrating a potential barrier (which is solved thanks to the Schrödinger equation ) and possessing a impedance greater than the kinetic energy that characterizes the same particle, ends up violating the principles of classical mechanics . This is the tunnel effect , a phenomenon that invites us to observe the movement of a quantum , since if it is oriented towards a classic slope or eventually energetic hill there are chances of studying it from its wave function .
Using Planck's law, we can establish the electromagnetic radiation that a black body that is in thermal equilibrium at a specific temperature is capable of emitting.
The Planck constant is very useful, on the other hand, within nanotechnology since it allows working in very small dimensions by applying quantum principles to manufacture, among other elements, semiconductors and transistors. It even helps to understand, as part of particle physics, the particularities of what are considered elementary particles , as well as contribute to the understanding of forces that influence the interactions produced between them.