Light has always been mysterious and attractive for people.He was associated with higher powers.Light gave life - and people understood it since ancient times.Proof - the cult of the light source - the sun.And because all the phenomena that man could not be explained on the basis of the knowledge that had occupied him tremendously.One of these phenomena, which are usually attentive person observes - the diffraction of light.What is it?
See the phenomenon may be personally if I miss a ray of light through a narrow hole and look at the spot of light that has passed through it.We will see that around the border - alternating dark and light bands.Why do we see just such a picture?
fact that the waves at certain points around the spot reinforce each other, and in some, in contrast, are in antiphase and therefore extinguish one another.Specific geometrical parameters to get a picture depends on the wavelength (and therefore for the waves of red and green light diffraction pattern will be different) and the diameter of the light beam.He becomes a cylindrical cone.This is the diffraction of light.But the phenomenon of the interaction of waves is called interference.Such a phenomenon is the name of the 19th century.Interference and diffraction of light - phenomena that are often described in physics textbooks.
What is the practical application of this physical phenomenon?His take into account when creating optical devices (cameras, microscopes, telescopes), because they all have a lens that limits its rim light beam.
Distinguish diffraction in the near field (the point on which a concrete beam is close to the obstacle).This phenomenon is the name of the Fresnel diffraction.But if the diffraction is in the far field (interacting rays are nearly parallel), the physicist would call her Fraunhofer diffraction.She has a curious feature: if the hole is large enough, the diffraction remain inconspicuous.
also in physics textbooks, we are confronted with the term diffraction grating.What it is?The optical device, which is a transparent or reflective plate with applied parallel strokes.When it passes through white light, it can be seen the separation of the light spectrum.Yes, the lattice becomes painted in the colors of the rainbow.Prism provides only a single range, and grill - a few.He was not alone, because the light is split into beams formed different bands and spectra of the longer, the greater the angle of deflection of light from the original direction.
However, because you can pass through the grille not only white light.But also light transmitted through a substance.This procedure is called spectral analysis, and reveals the composition of the samples.According to how the rays left after passing through the diffraction grating, it is possible to identify with what the researcher is dealing with.
Yes, and you, too, we have seen a diffraction grating, just seen.Doubt?It was when the last time you were holding the drive to the computer.He played beautifully all colors of the rainbow.You have seen, without realizing it, the phenomenon of light diffraction.The area on the disk on which the data are microscopic hillocks (therefore drive is so sensitive to damage), and the recording is done in a circle, so the surface of the laser disk - solid grating.
However, consider the diffraction phenomenon more closely.And find out what the diffraction of light, if you explain in simple language.So, if the rays meet an impermeable barrier, the rays passing near the very edge of this, do not go right, the waves seemed to wrap around the obstacles they encountered on the way.Through this process, the wave is capable of fully bend around objects which are greater than its length.
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