Electric current, definition

Now the effective conductivity ia the direction of the electric field is <7/(1 + /5 ), ie, the scalar conductivity reduced by a factor of (1 + /5 ) by the magnetic field. Also, the electric current no longer flows in the direction of the electric field a component j exists which is perpendicular to both the electric and magnetic fields. This is the Hall current. The conductivity in the direction of the Hall current is greater by a factor of P than the conductivity in the direction of the electric field. The calculation of the scalar conductivity starts from its definition ... 

The cell is the basis of all electrolysis. The anode admits current into the electrolyte and the cathode serves as a means of exit for the electrical current. The electrical flow provides a definition for electrolysis the flow of current from the anode through the electrolyte and out of the cell through the cathode with ensuing decomposition of the electrolyte, with products being formed at the electrodes. 

The term electrochromism was apparently coined to describe absorption line shifts induced in dyes by strong electric fields (1). This definition of electrocbromism does not, however, fit within the modem sense of the word. Electrochromism is a reversible and visible change in transmittance and/or reflectance that is associated with an electrochemicaHy induced oxidation—reduction reaction. This optical change is effected by a small electric current at low d-c potential. The potential is usually on the order of 1 V, and the electrochromic material sometimes exhibits good open-circuit memory. Unlike the well-known electrolytic coloration in alkaU haUde crystals, the electrochromic optical density change is often appreciable at ordinary temperatures. 

It is well to remember that in the past, the unit of electrical current—the international ampere—was defined as the strength of an invariant current which, when sent throngh a silver nitrate solution, would deposit l.lllSOOmg silver at the cathode. Today, another definition of the ampere as an SI unit is valid. 

Electrochemical interfaces are sometimes referred to as electrified interfaces, meaning that potential differences, charge densities, dipole moments, and electric currents occur. It is obviously important to have a precise definition of the electrostatic potential of a phase. There are two different concepts. The outer or Volta potential ij)a of the phase a is the work required to bring a unit point charge from infinity to a point just outside the surface of the phase. By just outside we mean a position very close to the surface, but so fax away that the image interaction with the phase can be ignored in practice, that means a distance of about 10 5 — 10 3 cm from the surface. Obviously, the outer potential i/ a U a measurable quantity. 

Rate of Electrochemical Reaction in Terms of Current. In this part of the derivation we start with a definition of the rate of reaction and the definition of the electric current. The rate of the reduction reaction v, reaction (6.6) from left to right, is defined as the number of moles m of Ox reacting per second and per unit area of the electrode surface ... 

A seemingly minor technical problem, the ability of triphenylmethyl to pick up virtually any solvent as solvent of crystallization, occupied Gomberg for some time and led him into consideration of then fashionable structures involving tetravalent oxygen, which were later abandoned. Another sidetrack, more serious in view of the absence of a useful theory, was caused by experiments based on the known fact that triphenylchloromethane showed salt-like conductivity in solution in liquid SO2 It was thus definitively established that there are carbonium salts in the true sense of the definition applied to salts. When triphenylmethyl was dissolved in liquid SO2, it was found that it too conducted the electric current quite well. " How should one explain this strange phenomenon, a hydrocarbon behaving like an electrolyte ... 

Electrochemistry, according to the definition given in Perry .s, is the science which treats of the chemical changes produced by an electric current and of the production of electricity from the energy of chemical reactions. Theoretically, the two branches are of equal importance. Industrially, however, the chemical and physical changes produced by the use of an electric current are by far the most important... 

The formula is derived as follows Electrical current, measured in amperes, is the rate of flow of electrical charge (coulombs), by definition, it is... 

The definition of a sensor is that it reacts to a parameter (for example, the volume of the mercury pool in a thermometer increases with temperature), and the intensity of the reaction is in relation to the parameter - for example, the measurement of an electrical current that is in relation to the concentration of the analyte oxidised or reduced at the electrode surface. The parameter to be investigated is the concentration of the analyte, while the parameter measured is an electrical current. As for the real devices, ultimately most signals are being transformed into electric ones. Electroactive materials are consequently of utmost importance with respect to intelligent textiles. Of course, apart from technical considerations, concepts, materials, structures and treatments must focus on the appropriateness for use in or... 

Electrochemistry deals with charged particles that have both electrical and chemical properties. Since electrochemical interfaces are usually referred as electrified interfaces, it is clear that potential differences, charge densities, dipole moments, and electric currents occur at these interfaces. The electrical properties of systems containing charged species are very important for understanding how they behave at interfaces. Therefore, it is important to have a precise definition of the electrostatic potential of a phase [1-6]. Note that what really matters in electrochemical systems is not the value of the potential but its difference at a given interface, although it is illustrative to discuss its main properties. 

Regarding the correct terminology, there are several references and examples of the term molecular wire . In some cases, it describes a system with a very specific behavior. In others, it simply refers to the structural features of the molecule under consideration. Thus, finding a clear definition is a rather difficult task. In 1998 an attempt was made by Emberly and Kirczenow [1] and a molecular wire has been defined as a molecule between two reservoirs of electrons . Nitzan and Ratner, on the other hand, called it a molecule that conducts electrical current between two electrodes [2], Most appropriate with respect to the topic of this thesis, we should stick to a rather restricted definition by Wasielewski, which classifies a molecular wire as a device that conducts in a regime, wherein the distance dependence (of electron transfer) may be very weak [3]. 

Driven by the energy produced in these reactions, electrons move spontaneously through the external electric circuit containing the load (i.e. a device powered by electric current). According to the definition, the system in the configuration of Figure 3.1.5 operates as a galvanic cell. The Ag electrode is termed the cathode because... 

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