Properties of Light

What is the wavelength of radiation in your microwave oven, whose frequency is 2.45 GHz  

SOLUTION First recognize that 2.45 GHz means 2.45 X 10 Hz = 2.45 X 10 s . From Equation 18-1, we write 

Test Yourself What is the frequency of green light with A = 500 nm (Answer 6.00 X 10 S = 600 THz) 

Following the discovery of the Antarctic ozone hole in 1985, atmospheric chemist Susan Solomon led the first expedition in 1986 specifically intended to make chemical measurements of the Antarctic atmosphere by using high-altitude balloons and ground-based spectroscopy. The expedition discovered that ozone depletion occurred after polar sunrise and that the concentration of chemically active chlorine in the stratosphere was l(X) times greater than that predicted from gas-phase chemistry. Solomon s group identified chlorine as the culprit in ozone destruction and polar stratospheric clouds as the catalytic surface for the release of so much chlorine. 

Light can also be thought of as particles called photons. The energy, E (measured in joules, J), of a photon is proportional to its frequency  

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It is well known that a light beam carries momentum and tliat tire scattering of light by an object produces a force. This property of light was first demonstrated by Frisch [K)] tlirough tire observation of a very small transverse... 

Properties of Light and Heavy Hydrogen. Vapor pressures from the triple point to the critical point for hydrogen, deuterium, tritium, and the various diatomic combinations are Hsted in Table 1 (15). Data are presented for the equiUbrium and normal states. The equiUbrium state for these substances is the low temperature ortho—para composition existing at 20.39 K, the normal boiling point of normal hydrogen. The normal state is the high (above 200 K) temperature ortho—para composition, which remains essentially constant. 

Properties of Light and Heavy Water. Selected physical properties of light and heavy water are Hsted ia Table 3 (17). Thermodynamic properties are given ia Table 4. The Hquid plus vapor critical-temperature curve for xT) (1 )H2 ) mixtures over the entire concentration range has been reported (28). 

Table 3. Physical Properties of Light and Heavy Water...

Benedict, Manson, Webb, George B., and Rubin, Louis C., An Empirical Equation for Thermodynamic Properties of Light Hydrocarbons and Then Mixtures, Chemical Engineering Progress, Vol. 47, No. 8, August, 195 I pp. 419-422. 

A hundred years ago it was generally supposed that all the properties of light could be explained in terms of its wave nature. A series of investigations carried out between 1900 and 1910 by Max Planck (1858-1947) (blackbody radiation) and Albert Einstein (1879-1955) (photoelectric effect) discredited that notion. Today we consider light to be generated as a stream of particles called photons, whose energy E is given by the equation... 

Before we can analyze the spectrum of hydrogen atoms, we must become more familiar with light. In Chapter 14 light was characterized by frequency or wavelength. (Reread Section 14-3.1.) Now we shall consider another property of light... 

Statistical properties of light are described within the framework of quantum optics which is based on a quantized description of the electromagnetic field. In section 21.2 we will depict specific experimenfs which have been performed fo show fhaf a quanfum description is necessary in some cases. We will describe in Section 21.3 fhe sfandard fools for fhe analysis of fhe sfafisfical properties of lighf and give fhe resulfs obfained for a number of sources. 

The most useful tool for studying the structure of atoms is electromagnetic radiation. What we call light is one form of this radiation. We need to know about the properties of light in order to understand what electromagnetic radiation reveals about atomic stmcture. 

Heinrich Hertz in 1887 who used an oscillating circuit of small dimensions to produce electromagnetic waves which had all of the properties of light waves... 

Quantum theory started as an explanation of electromagnetic effects (black-body radiation) in terms of corpuscular properties of light, expressed... 

But light is also a particle. Some properties of light cannot be explained by the wave-like nature of light, such as the photoelectric effect and blackbody radiation (see Section 9.4), so we also need to think of light comprising particles, i.e. photons. Each photon has a direction as it travels. A photon moves in a straight line, just like a tennis ball would in the absence of gravity, until it interacts in some way (either it reflects or is absorbed). 

The International Association for the Properties of Water and Steam (IAPWS) provides internationally accepted values and formulations for the properties of light and heavy steam, water, and selected aqueous solutions for scientific and industrial applications. IAPWS Releases and Guidelines can be obtained online at http //www.iapws.org. 

C. Fou, O. Onitsuka, M. Ferreira, M.F. Rubner, and B.R. Hsieh, Fabrication and properties of light-emitting diodes based on self-assembled multilayers of poly(phenylene vinylene), J. Appl. Phys., 79 7501-7509, 1996. 

From Snell s Law, sin(0j) m = sin(0j) nr. We have TIR when sin(Oj) > nr/rii, while we will have refraction and reflection when sin(0j) < nr/ni. In practical cases properties of light, such as phase, polarization and intensity, can be modulated inside the wave guide by a given measurand, which is interacting, for instance, with a CIM lying within the penetration depth for the evanescent field of the light localized near the external guide surface. 

The polarization properties of light in combination with fluorescence can be used as a powerful tool for determining motional properties of membranes. This is possible due to the fact that the time scale of interest for membrane lipids falls within the time frame of the fluorescence decay phenomena (0-100+ ns). This, coupled with high sensitivity, low perturbing properties of fluorescent probes, and the large number of available probes, makes the fluorescence approach the method of choice for membrane motional studies. 

Melinger JS, Pan YC, Kleiman VD, Peng ZH, Davis BE, McMorrow D, Lu M (2002) J Am Chem Soc 124 12002-12012 Optical and photophysical properties of light-harvesting phenylacetylene mono-dendrons based on unsymmetrical branching... 

Alter, David, On certain physical properties of light produced by the com-... 

Ellipsometiy is the technique that uses changes in the polarization properties of light when it strikes the object of investigation to determine the properties thereof. As will be seen, it allows one to calculate the thickness of extremely thin layers on electrodes and gather some information as to the identity of what is present. This remarkable technique is sensitive to less than one-tenth of a monolayer. 

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