Electromagnetic radiation, energy wavelengths

Solar energy is defined as the radiant energy transmitted by the Sun and intercepted by Earth. It is transmitted through space to Earth by electromagnetic radiation with wavelengths ranging between 0.20 and 15 pm. The availability of solar fiux for terrestrial applications varies with season, time of day, location, and collecting surface orientation. In this section, we shall treat these matters analytically (Kutz, 2007). 

Figure 1.1. Spectrum of electromagnetic radiation A0 - wavelength in free space, W = hu quantum energy, vr - lowest resonance frequency in the rotational spectrum of water, up - plasma frequency of the ionosphere. Reprinted with the permission from [2],...

The discussion in this chapter will be limited to the absorption of electromagnetic radiation of wavelengths from about 1000 A to perhaps 10000 A or from say 12 electron volts down to 1 or 2 electron volts. Mention will be made when possible of the effects of charged particles with corresponding energies, but such studies are so rare as not to constitute an important part of the chapter. 

During microwave-assisted extraction (MAE), microwave energy is applied to heat a solvent or/and a sample in order to speed up transfer of the compound of interest from the sample to the solvent [43, 44]. Microwaves are an electromagnetic radiation with wavelengths ranging from as long as 1 m to as short as 1 mm, with frequencies between 1 and 100 GHz. 

Using this form of the eqnation, we can calculate the mass associated with a given quantity of energy. For example, we can calculate the apparent mass of a photon For electromagnetic radiation of wavelength A, the energy of each photon is given by the expression... 

Microwave energy is a form of electromagnetic radiation with wavelengths between 1 mm and 1 m (located between infrared radiation and radio frequencies). Microwave irradiation was first proposed as a heating method several decades ago, but it was during the last decade that it rapidly became a well-established technique for different chemical reactions... 

Radiation. Radiant heat transfer occurs in the form of electromagnetic radiation with wavelengths from about 10" to 10" m this is known as thermal radiation. The visible spectrum is centred on wavelengths of 5x 10" m. The total energy flux emitted by a body at an absolute temperature T is given by... 

Infrared spectra arise from the interaction between matter and electromagnetic radiation of wavelength between about 2 and 50 jjm (respectively 5000 and 200 cm ). The energy associated with such radiations corresponds to transitions between vibrational levels of the ground electronic state of molecule. The absorbance is determined by Beer s law. 

Microwaves are a form of electromagnetic radiation with wavelengths ranging from as long as one metre to as short as one millimetre, or equivalently, with frequencies between 300 MHz (0.3 GhZ) and 300 GHz. They have energies in the range 0.0100-1.00 kj moTh... 

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