The beam angle


2018-03-28 21:22:13




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Today we will reveal, what is the angle of refraction of the electromagnetic wave (light) and how are its laws.

Eyes, skin, brain

angle of refraction

Man has five basic senses. Medical scientists distinguish up to eleven different dissimilar sensations (e.g. feeling of pressure or pain). But the basic information people receive through the eyes. Up to ninety percent of the available facts the human brain recognizes as electromagnetic waves. So the beauty and aesthetics of the people basically understand visually. The angle of refraction of light plays an important role.

Desert, a lake, rain

the angle of light refraction

The World around is permeated with sunlight. Air and water form the basis of what people are like. Of course, has its own rugged beauty in an arid desert landscapes, but most people still prefer some moisture.

Man has always been fascinated by mountain streams and flowing lowland rivers, tranquil lakes and the forever rolling waves of the sea, the spray of the waterfall and the cold sleep of the glaciers. Not just everyone notice the beauty of the play of light in the dew on the grass, sparkling frost on the branches, milky white fog and dark delights of the low clouds. And all these effects are created through the refraction angle of the beam in the water.

Eyes of the electromagnetic scale, the rainbow

the angle of refraction the index of refraction

The Light – this oscillation of the electromagnetic field. Wavelength and its frequency determines the form of a photon. The frequency of oscillations depends on whether it's a radio wave, infrared ray, visible to humans spectrum of a color, ultraviolet light, x-rays or gamma rays. People are able to perceive with the eyes of electromagnetic waves with wavelengths between 780 (red) to 380 (violet) nanometers. On a scale of all possible waves, this site covers a very small area. That is a big part of the electromagnetic spectrum people are not able to accept. And all of the available beauty creates the difference between the angle of incidence and angle of refraction on the border environments.


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Vacuum, Sun, planet

The Photons emitted by the Sun as a result of the fusion reaction. The fusion of hydrogen atoms and the birth of helium accompanied by the release of huge number of different particles, including photons of light. In a vacuum electromagnetic waves propagate in a straight line and as fast as possible. When injected into a transparent and denser medium, for example, in the earth's atmosphere, the light changes the velocity of propagation. As a result, it changes the direction of propagation. How, determines the refractive index. The angle of refraction is calculated according to the formula of Snellius.

Snell's Law

The Dutch mathematician Willebrord Snell worked all my life with angles and distances. He figured out how to measure distances between cities, how to find a given point on the sky. No wonder he found a pattern of angles of refraction of light.

The Formula of the law looks like this:

  • N1Sin θ1 = n2Sin θ2.

In this expression, the symbols have the following meanings:

  • N1 and n2 – the refractive index of medium one (from which a beam) and environment 2 (it falls);
  • θ1 and θ2 – is the angle of incidence and refraction of light respectively.

Explanation of the law

It is Necessary to give some explanation to this formula. Angles θ is the number of degrees which lies between the direction of propagation of the beam and the normal to the surface at the tangent point of the light beam. Why this is normal? Because in reality strictly flat surfaces do not exist. But to find the normal to any curve is quite simple. Besides, if the task is known the angle between the boundary of the mediums and the incident beam of x to the desired angle θ – it's only (90º-x).

Most Often the light comes from the more rarefied (air) to denser (water) medium. The closer to each other and are atoms of the medium, the stronger refracted ray. Therefore, the denser the environment is, the greater the angle of refraction. But happens and on the contrary: the light falls from air to water or from air to vacuum. Under such circumstances, it may be a condition in which n1Sin θ1>n2. That is, the entire beam will be reflected back into the first medium. This phenomenon is called total internal reflection. The angle at which comes the above-described circumstances, is called a limit angle of refraction.

What determines the refractive index?

This value depends only on the properties of the substance. For example, there are crystals for which the value of the angle at which the beam enters. Anisotropy of properties is manifested in the birefringence. There is environment, which are important for the polarization of the incoming radiation. It should also be remembered that the angle of refraction depends on the wavelength of the incident radiation. It is on this difference is based the experience with the separation of white light into a rainbow by a prism. It should be noted that ambient temperature also affects the refractive index of the radiation. The faster you oscillate the atoms of the crystal, the more deformed its structure and the ability to change the direction of light propagation.

Examples of values of the refractive index

the angle of refraction of the glass

We Give different values for familiar environments:

  1. Salt (chemical formula NaCl) asthe mineral has the name "halite". Its refractive index – 1,544.
  2. Angle of refraction of the glass is calculated from its refractive index. Depending on the type of material this value varies between 1,487 and 2,186.
  3. Diamond is renowned for the play of light in it. Jewelers take into account all of the plane when cut. The refractive index of diamond is-2,417.
  4. Water, free from impurities, refractive index – 1,333. H2O – a very good solvent. Therefore, chemically pure water in nature. Each structure, each river is characterized by its composition. Consequently, the refractive index changes. But for simple school tasks can take and a value.

Jupiter, Saturn, Callisto

the critical angle of refraction

Up To this point we talked about the beauty of the earthly world. The so-called normal conditions mean a very specific temperature and pressure. But there are other planets in the Solar system. There is the usual very different landscapes.

On Jupiter, for example, it is possible to observe a haze of argon in the methane clouds, and the upward flow of helium. There is also the usual x-ray auroras.

Saturn tanouye the mists shrouded a hydrogen atmosphere. On the lower layers of the planet of the very hot methane clouds are diamond rains.

This rocky frozen Jupiter's moon Callisto has an internal ocean, which is rich in hydrocarbons. Perhaps in the depths of his living absorbing sulfur bacteria.

And in each of these landscapes, the beauty creates a play of light on different surfaces, edges, ledges and clouds.

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