Wave Optics | - what is the relation between wavelength and-askIITians
Answer to GOAL Use the index of refraction to determine the effect of a into the speed of light in media equation and the wavelength in media equations. Wavelength and the Index of Refraction of refraction, we find a relationship between the wavelength = v/f in a medium and the wavelength 0 = c/f in vacuum: . the purpose of studying about refractive index (u) is to know whether the Wavelength is inversely proportional to refractive dubaiairporthotel.infoe.
Since the refractive index of the ionosphere a plasmais less than unity, electromagnetic waves propagating through the plasma are bent "away from the normal" see Geometric optics allowing the radio wave to be refracted back toward earth, thus enabling long-distance radio communications.
See also Radio Propagation and Skywave. Negative index metamaterials A split-ring resonator array arranged to produce a negative index of refraction for microwaves Recent research has also demonstrated the existence of materials with a negative refractive index, which can occur if permittivity and permeability have simultaneous negative values.
The resulting negative refraction i. Ewald—Oseen extinction theorem At the atomic scale, an electromagnetic wave's phase velocity is slowed in a material because the electric field creates a disturbance in the charges of each atom primarily the electrons proportional to the electric susceptibility of the medium.
Similarly, the magnetic field creates a disturbance proportional to the magnetic susceptibility.
As the electromagnetic fields oscillate in the wave, the charges in the material will be "shaken" back and forth at the same frequency. The light wave traveling in the medium is the macroscopic superposition sum of all such contributions in the material: This wave is typically a wave with the same frequency but shorter wavelength than the original, leading to a slowing of the wave's phase velocity. Most of the radiation from oscillating material charges will modify the incoming wave, changing its velocity.
However, some net energy will be radiated in other directions or even at other frequencies see scattering. Depending on the relative phase of the original driving wave and the waves radiated by the charge motion, there are several possibilities: This is the normal refraction of transparent materials like glass or water, and corresponds to a refractive index which is real and greater than 1.
This is called "anomalous refraction", and is observed close to absorption lines typically in infrared spectrawith X-rays in ordinary materials, and with radio waves in Earth's ionosphere.
Refractive Index (Index of Refraction) | MicroscopyU
It corresponds to a permittivity less than 1, which causes the refractive index to be also less than unity and the phase velocity of light greater than the speed of light in vacuum c note that the signal velocity is still less than c, as discussed above. If the response is sufficiently strong and out-of-phase, the result is a negative value of permittivity and imaginary index of refraction, as observed in metals or plasma.
This is light absorption in opaque materials and corresponds to an imaginary refractive index. If the electrons emit a light wave which is in phase with the light wave shaking them, it will amplify the light wave.
This is rare, but occurs in lasers due to stimulated emission.
Wavelength and the Index of Refraction
It corresponds to an imaginary index of refraction, with the opposite sign to that of absorption. Distilled water is a particularly convenient standard since it is nontoxic, readily available in pure form, and its refractive index varies only slightly with temperature Table 1.
If you find that the index of refraction of the standard is consistently off by more than 0.RELATION BETWEEN VELOCITY, FREQUENCY AND WAVELENGTH
Probably the most common source of error in analog refractometers is misreading of the scale. If the index of refraction you determined seems inconsistent with other data, try repeating the measurement. Determining Concentrations of Solutions Determining the concentration of a solute in a solution is probably the most popular use of refractometry.
For example, refractometer-based methods have been developed for determining the percentage of sugar in fruits, juices, and syrups, the percentage of alcohol in beer or wine, the salinity of water, and the concentration of antifreeze in radiator fluid.
Many industries use refractometer-based methods in quality control applications. In most cases the refractive index is linearly or nearly linearly related to the percentage of dissolved solids in a solution Figure 2. By comparing the value of the refractive index of a solution to that of a standard curve the concentration of solute can be determined with good accuracy.
A much more detailed standard curve for the relationship between the refractive index and the percentage of sucrose is available as a PDF file.