النظرية الموجية للضوء - الضوء .. الفيزياء

The Wave Theory of Light - Light .. Physics

The Wave Theory of Light

In 1680, Christiaan Huygens presented a new theory that says that light travels in the form of waves. However, it lacked specific evidence for a century. It was possible to explain the reflection and refraction of light convincingly by the theory of the straight propagation of light.

The phenomenon of light interference had to be discovered and discovered in 1801 by Thomas Young in order for the wave theory of light to be established and become a reality. When two light waves of the same frequency are emitted from a single source, and they reach a certain point after having passed two different paths, each one interferes with the other and their total amplitude is equal to the sum of the amplitudes of each of them, so its value doubles in the case of constructive interference, and completely disappears in the case of destructive interference. The resulting interference pattern consists of a set of dark lines alternating with another set of bright lines. The bright line is formed when the difference between the path of the two waves, F, is equal to a whole number of the wavelength F = N A, where N represents one of the integers 1, 2, 3, 000. The line is dark when the path difference is a single multiple of half the wavelength F = N A / 2. The most prominent example of the interference phenomenon is the colors that form in soap bubbles and in thin oil films. It was not possible to explain the phenomenon of light interference without resorting to the wave theory of light, although this theory failed to explain the interaction between matter and rays. Planck had launched his famous postulate that the exchange of energy between rays and matter appears through the absorption or emission of matter by a small body of energy called a quantum. The photoelectric theory contributed to supporting this hypothesis, and later led to the creation of a concept that considers rays as a vapor of quanta called photons, and they travel in space at the speed of light itself. Depending on the existing conditions, light is considered either as a movement of the waves that compose it or as a movement of the particles it carries. This dual nature is not limited to radiation alone, but also applies to some other particles such as electrons. The wavelength accompanying the movement of the particle is related to the amount of their movement (i.e. the product of its speed and its mass) according to the following equation L = h m, where h represents Planck's constant. All of these concepts formed the basis of quantum theory.

The uncertainty principle established by Werner Heisenberg is one of the results of this theory, and states that it is impossible to make accurate and instantaneous measurements of some of the known properties of the particle. Such as its position S and the amount of its movement M, because these measurements contain some uncertainty in their value.

For example, observing a particle through a light beam leads to collisions between it and the photons that make up the beam, which disturbs the particle's position and changes its speed, which does not allow the amount of its movement and location to be determined accurately.

(Interference pattern resulting from two coherent light sources)
(Formation of bright and dark places through constructive and destructive interference)