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An EMF meter is a scientific instrument for measuring electromagnetic fields (abbreviated as EMF). Most meters measure the electromagnetic radiation flux density (DC fields) or the change in an electromagnetic field over time (AC fields), essentially the same as a radio antenna, but with quite different detection characteristics.
Bipolar electrochemistry scheme. In electrochemistry, standard electrode potential, or , is a measure of the reducing power of any element or compound.The IUPAC "Gold Book" defines it as; "the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode".
In fact, since the potentiometric measurement is a non-destructive measurement, assuming that the electrode is in equilibrium with the solution, we are measuring the solution's potential. Potentiometry usually uses indicator electrodes made selectively sensitive to the ion of interest, such as fluoride in fluoride selective electrodes , so that ...
The emf of the cell at zero current is the maximum possible emf. It can be used to calculate the maximum possible electrical energy that could be obtained from a chemical reaction. This energy is referred to as electrical work and is expressed by the following equation:
The applied voltage which is just sufficient to overcome the back EMF due to polarization and also to bring about the electrolysis of an electrolyte without any hindrance is known as decomposition potential. The decomposition potential Ed is composed of various potentials and is given by: Ea (min)= Ed= Eb+ Es+ Ev. where: Ea = applied potential
The galvanometer usually only measures the first term in the EMF which contributes the current in circuit, although sometimes it can measure the incorporation of the second term such as when the second term contributes part of the current which the galvanometer measures as motional EMF, e.g. in the Faraday's disk experiment.
The EMF of a concentration cell without transport is: E n t = R T F ln a 2 a 1 {\displaystyle E_{\mathrm {nt} }={\frac {RT}{F}}\ln {\frac {a_{2}}{a_{1}}}} where a 1 {\displaystyle a_{1}} and a 2 {\displaystyle a_{2}} are activities of HCl in the two solutions, R {\displaystyle R} is the universal gas constant , T {\displaystyle T} is the ...
The electromagnetic field is described by classical electrodynamics, an example of a classical field theory. This theory describes many macroscopic physical phenomena accurately. [ 6 ] However, it was unable to explain the photoelectric effect and atomic absorption spectroscopy , experiments at the atomic scale.