No matter how far the average person in their daily lives once passed by the school curriculum, it is a no-no and will make about yourself remember.That's what happens when it comes to the external appearance of the photoelectric effect.
Determination
photoelectric effect in physics is considered to be the process of alignment of electrons in atoms, molecules of a substance that occurs and takes place under the influence of light.A photoemission - a process in which the electrons are knocked out light with such force that fly over the outer limits of its substance.
bit of history and practice
the first time on this amazing fact noticed physicist Heinrich Hertz in Germany back in 1887.The study was continued opening Hertz counterpart, Russian physicist Stoletov.A genius, Einstein developed the theory of the photoelectric effect based on the ideas of quantum physics.Since photoemission studied deeply enough and versatile, and the resulting knowledge is applied in full in the design and manufacture of devices on the basis of solar cells.If you take the most basic example, this automatic gate to the garage working on solar cells.
mechanisms of this type operate on electricity.However, solar cells that use only external photoelectric effect, transform the energy obtained when radiation into electrical incompletely.Therefore, use them as a source of electricity is not much point, which is not true about automation.It was with the help of light beams occurs associated circuits in automatic control mechanisms.
is no exaggeration to assert that the discovery of the photoelectric effect was a truly revolutionary event in physics.Here are the most important of its consequences:
- scientists to reveal the secret nature of light, the light beam;
- of silent cinema was "talking" methods were invented voice, and the fact of moving images also became possible due to the photoelectric effect;
- creation on the basis of photoelectric devices such machines and "smart cars" that the specified parameters without human intervention made the various parts;
- many different mechanisms based on the photoelectron automation.
Thus, the very use of the photoelectric effect and become a breakthrough in modern technology.
Classification photocells
Photo Effects are divided into several types according to their properties and functions.
- external photoelectric effect (in other words - photoemission).Electrons are emitted beyond the matter when it occurs are called photoelectrons.And the electric current that they form when an orderly move in the external electric field, was called photocurrent.
- internal photoelectric effect, influencing the photoconductive material.It occurs when the electrons are redistributed for semiconductors and insulators depending on their energy state and aggregation - solid or liquid.The phenomenon of redistribution is influenced by light.It was then that increases the electrical conductivity of a substance that isphotoconductivity effect is obtained.
- Valve photoelectric effect - the transition of photoelectrons from their bodies into other solids (semiconductors) or liquid (electrolyte).
external photoelectric effect is the basis of the work of modern vacuum solar cells.They are made in the form of glass envelopes whose inner surface is partially covered with a thin layer of metallic deposition.A small thickness for low work output.Transparent window bulb passes into the light, and it is inside the anode in the form of a wire loop, or a disk captures the photoelectrons.If the anode is connected to the positive pole of the battery, the circuit will become isolated, it goes on electric current.IeVacuum solar cells can turn on or off the relay.
combining solar cells and relays, you can create a variety of "seeing" machines, for example, the machine in the subway.
So, being laid in the basis of many industrial processes, external photoelectric effect as a great physical discoveries were key to the successful operation of industrial automation.
