Transmission of electromagnetic radiation

A substance or device which allows the transmission of electromagnetic radiation of a specified wavelength range and does not allow transmission of radiation outside that range. See also Filter Cut-off Filter... 

Table 3.2 Spectral cutoff values for glass and plastics Uso = wavelength at which transmission of electromagnetic radiation is reduced to 50%)...

Transmission of electromagnetic radiation does not need a medium for its propagation. The wavelength spectrum of the radiation depends on the nature and tanperature of the... 

Transmission of electromagnetic radiation does not need a medium for its propagation. The wavelength spectrum of the radiation depends on the nature and temperature of the heat source. Every body emits radiation due to its temperature level, which is called thermal radiation because it generates heat. The wavelength range of thermal radiation is 0.1 100 pm within the spectrum. IR radiation falls in this category and is conventionally classified as (Sandu, 1986) near IR (0.75 3.00 pm), medium IR (3.00-25 pm), and far IR (25 100 pm). 

De Broglie s hypothesis of matter waves received experimental support in 1927. Researchers observed that streams of moving electrons produced diffraction patterns similar to those that are produced hy waves of electromagnetic radiation. Since diffraction involves the transmission of waves through a material, the observation seemed to support the idea that electrons had wave-like properties. 

Radiation is fundamentally different from conduction as it describes the transfer of heat between two substances that are not in contact with each other. Like conduction, radiation is an independent form of heat transfer. Ignoring the conflicts of wave and quantum theory, radiation, refers to the transmission of electromagnetic energy through space. 

Spectroelectrochemistry, reflection mode — The interaction of electromagnetic radiation with matter (-> spectroscopy) may occur by absorption or scattering when radiation impinges on matter or passes through matter. In the latter case (transmission mode) the radiation before and after passage is evaluated in order to obtain the desired spectrum. In studies of opaque materials or of surfaces interacting with matter inside the (bulk)... 

The depth of introduction can be varied by technical tools as well. Transmission techniques can be applied for bulk analysis, while reflection techniques are appropriate to the study of the interfaces. Transmission and reflection techniques can be applied using a wide range of electromagnetic radiation, from infrared to x-ray ranges. Moreover, particle radiation (e.g., the neutron scattering technique) can also be used for the study of the structure of interfaces. 

Spectroscopy is in general terms the science that deals with the interaction of electromagnetic radiation with matter in particular, it can be said to be the investigation of the optical properties, i. e. the transmission or reflection, of a sample within a certciin spectral range. These properties are studied as a function of the wavelength or frequency of the incident electromagnetic radiation. The spectral range mainly under consideration here is the infrared. 

Thus, if a transition exists which is related to the frequency of the incident radiation by Planck s constant (h = 6.626-1 O 34), then the radiation can be absorbed. Conversely, if the frequency (v) does not satisfy Planck s expression, then the radiation will be transmitted. A plot of the frequency of the incident radiation against some measure of the percent radiation absorbed by the sample provides the absorption spectrum of the compound or component. The absorption spectrum is characteristic for the compound and this spectrum is often called the fingerprint of the compound. Infrared spectroscopy is based on the measurement of the absorption of electromagnetic radiation that arises from the altering of the vibration level of the component s molecule. An example of the adsorption and transmission of the infrared radiation is shown in Figure 2.30. 

The reflection and refraction of electromagnetic radiation at an interface can be discussed with relation to Fig. 2. The incident, reflected, and refracted rays are shown in this figure as I, R, and T and reflection and transmission coefficients can be derived straightforwardly from standard electromagnetic theory. In order to focus our ideas and to define the convention used in this section, we may write down the expression for the electric field, E, of the radiation, assuming that the light is propagating in the z direction (with unit vector ) and the electric field is oriented in the x direction (with unit vector... 

Many of the properties of electromagnetic radiation are conveniently described by means of a classical sinusoidal wave model, which embodies such characteristics as wavelength, frequency, velocity, and amplitude, in contrast to other wave phenomena, such as sound, electromagnetic radiation requires no supporting medium for its transmission and thus passes readily through a vacuum. 

Radio frequency (1915) (RF) n. A frequency of electromagnetic radiation within the broad range of radio and radar transmission, e.g., from about 300kHz to 20GHz. Serway RA, Faugh JS, Beimett CV (2005) College physics. Thomas, New York. 

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