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In other media, any stream of charged objects (ions, for example) may constitute an electric current. To provide a definition of current independent of the type of charge carriers, conventional current is defined as moving in the same direction as the positive charge flow. So, in metals where the charge carriers (electrons) are negative ...
The term DC is used to refer to power systems that use only one electrical polarity of voltage or current, and to refer to the constant, zero-frequency, or slowly varying local mean value of a voltage or current. [9] For example, the voltage across a DC voltage source is constant as is the current through a direct current source.
The limiting current in electrochemistry is the limiting value of a faradaic current that is approached as the rate of charge transfer to an electrode is increased. The limiting current can be approached, for example, by increasing the electric potential or decreasing the rate of mass transfer to the electrode. It is independent of the applied ...
alternating current (AC) A form of electric current in which the movement of electric charge periodically reverses direction. Contrast direct current. ammeter An instrument that is used to measure electric current. amorphous solid A type of solid which does not have a definite geometric shape. ampere (A) Often abbreviated as amp.
For example, gaseous oxygen (O 2) and hydrogen (H 2) can be combined in a fuel cell to form water and energy, typically a combination of heat and electrical energy. [ 25 ] Conversely, non-spontaneous electrochemical reactions can be driven forward by the application of a current at sufficient voltage .
Electric current is the flow of electric charge through an object. The most common charge carriers are the positively charged proton and the negatively charged electron . The movement of any of these charged particles constitutes an electric current.
A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step-up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step-down transformer, C=consumers.
This is a list of unsolved problems in chemistry. Problems in chemistry are considered unsolved when an expert in the field considers it unsolved or when several experts in the field disagree about a solution to a problem.