refractive index | Definition & Equation | serii.info
5 days ago related topics Some typical refractive indices for yellow light (wavelength equal to nanometres [10−9 metre]) are the The equation n = c/v in this case indicates, correctly, that the velocity of X-rays in glass and in other. 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: . following topics: • Dispersion usually denoted as nd – the refractive index at the wavelength As Abbe demonstrated, the following linear relationship will.
During the last decade, numerous practical devices based on the principle described above using various cuvettes have been constructed for determining the refractive index [ 6 - 9 ]. The refractive index varies with concentration, temperature, pressure, and wavelength [ 2 - 71011 ]. Recent studies [ 2 - 4 ] provided the detailed study on the concentration mapping by the measurement of refractive index of liquids. Temperature coefficient of refractive index can also be used to calculate thermal expansion coefficient [ 24 ].
Several techniques are reported in literature for the measurement of concentration and temperature dependence of refractive index of sugar solution using various techniques [ 2 - 7 ]. Various techniques have been developed to determine the contents of sugar in solutions [ 12 - 14 ].
The techniques are Inter digital Capacitor Sensor to determine the contents of sugar in solution [ 12 ]; optical Coherence Tomography to determine blood glucose concentration in diabetic patients [ 13 ]; Quantification of sugar in soft drinks and fruit juices by Density, refractometry, infrared spectroscopy and statistical methods [ 14 - 16 ] are some of the techniques so far developed.
The above mentioned techniques are industrial made instrument used to determine the concentration of sugar in solution. Such kind of instrument is very expensive and also not available in most laboratories. Materials and Methods Materials Locally constructed equilateral hollow prism, Red and Green Diode laser, He-Ne laser as light sources, digital electronic balance with a good accuracy for mass measurement were used.
In addition, different apparatus such as measuring cylinder to measure the volume of water, mercury thermometer to control the temperatures of the solutions and magnetic stirrer with hot plate for heating and mixing the solution. In addition, deionized water as solvent, locally produced sugar and soft drink beverages Pepsi, Coca, 7up, Sprite, Mirind and Fanta were used as our sample. Calibration curve developed from the graph of refractive index versus the concentration of the solution.
Numerical procedure of fitting the experimental data was carried out by linear curve fitting using origin 8 software. A theory and method for derivation of refractive index have been discussed elsewhere [ 1 - 25 ].
The angle of incidence is responsible for deviation produced in the path of light beam. A monochromatic source of light Red, Green Diode laser and He-Ne laser was allowed to fall at angle of incident on the face of the liquid prism and the angle of minimum deviation was determined for each laser light.
During the measurement the solutions were filtered before pouring into the hollow prism.
Refraction of light
The hollow prism was also rinsed carefully after every measurement. Each measurement has taken three times.
Experimental set up for the measurements of angle of minimum deviation using prism spectrometer. Methods of measuring temperature dependent refractive The temperature dependent refractive indices of the solution measured at the temperatures The solutions were heated using magnetic stirrer with hot plate and its temperature controlled by placing the thermometer inside a solution. The angle of minimum deviation was measured at the interval of 5 K while the solution is cooling down from highest to lowest temperature.
Almost all solids and liquids have refractive indices above 1. Aerogel is a very low density solid that can be produced with refractive index in the range from 1.
Wavelength and the Index of Refraction
Most plastics have refractive indices in the range from 1. Moreover, topological insulator material are transparent when they have nanoscale thickness. These excellent properties make them a type of significant materials for infrared optics. The refractive index measures the phase velocity of light, which does not carry information.
Refractive index - Wikipedia
This can occur close to resonance frequenciesfor absorbing media, in plasmasand for X-rays. In the X-ray regime the refractive indices are lower than but very close to 1 exceptions close to some resonance frequencies. 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.Refraction and Refractive Index
Depending on the relative phase of the original driving wave and the waves radiated by the charge motion, there are several possibilities: