It all started with a simple experiment during the 20th century. By shining a light on a piece of metal, it was expected that the electrons would obtain the necessary energy from the light to move away from the surface and fly around. After that, the next step would be to just point a detector at this metal to measure the energy of the electrons, in a phenomenon known as the photoelectric effect.
Scientists at the time claimed that light was made of waves of electricity and magnetism, which would imply the possibility that electrons accumulate enough energy to break away from the surface, regardless of the frequency of the light.
But that’s not what happened. Instead, only light above a certain frequency could make the electrons move, and they always left the metal with the same energy, no matter how intense the light.
Einstein’s contribution
The result of this experiment changed physics forever. What could have happened? It was then that Albert Einstein, one of the best-known physicists in human history, arrived on the scene.
As incredible as it may seem, it didn’t take long for him to formulate his hypothesis on the subject. He hypothesized that what we perceive as choppy, rippling waves of electricity and magnetism were actually a flood of small, discrete, distinct and indivisible beams of luminous matter, that is, for Einstein, light was quantized.
Albert Einstein: the legendary physicist who, among other contributions, discovered the photon. Source: Getty Images
This means that, instead of transferring a continuous stream, light transfers its energy in well-defined amounts, proportional to its frequency. This quantity was called light quantum by Einstein..
Each quantum represents the smallest amount of light material you can have. And since these beams cannot be cut, it is not possible to have fractional proportions of light matter. You can have one unit of luminous material, two units of luminous material, and so on, but never 1.34, for example, or any other fractional number.
This solved the problem of the photoelectric effect, and this hypothesis has not been refuted to this day. Electrons need a certain amount of energy to move away from a metal. And this energy is not determined by the brightness or intensity of the light, but by its frequency.
Higher frequencies correspond to more energetic photons (the name given to particles). If the energy was too slow, the electrons would never be able to escape the metal. When the photon hits the electrons, they deposit a specific, fixed amount of energy, explaining why they always escaped in exactly the same way..
The quantum revolution
The discovery of the photon by Einstein was a true revolution in the entire world of science. One of the differences between classical physics and what became known as quantum mechanics is the fact that observation changes the way we see matter.
In other words, it was previously believed that, regardless of how the observation was made, the state of a particle would never change, as it would be exact. However, the discovery of the photon changed this perspective.
This because the act of impact of this quantum particle generates influencesculminating in one of the main postulates of this theory: the act of observation changes the state of a quantum system.
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2023-11-19 14:00:00
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