Chapter 19
Electric Current and Resistance
By Boundless
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A battery is a device that converts chemical energy directly to electrical energy.
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The electrical current is directly proportional to the voltage applied and inversely related to the resistance in a circuit.
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The drift velocity is the average velocity that a particle achieves due to an electric field.
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Ohm's Law states that current is proportional to voltage; circuits are ohmic if they obey the relation V=IR.
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Superconductivity is a phenomenon of zero electrical resistance and expulsion of magnetic fields in certain materials below a critical temp.
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Resistance and resistivity describe the extent to which an object or material impedes the flow of electric current.
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Resistivity and resistance depend on temperature with the dependence being linear for small temperature changes and nonlinear for large.
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Phasors are used to analyze electrical systems in sinusoidal steady state and with a uniform angular frequency.
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The root mean square (RMS) voltage or current is the time-averaged voltage or current in an AC system.
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Electrical safety systems and devices are designed and widely used to reduce the risks of thermal and shock hazards.
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The hazards from electricity can be categorized into thermal and shock hazards.
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Voltage pulses along a cell membrane, called action potentials, allow us to sense the world, control parts of our body, and think.
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Electric energy stimulating the heart occurs in the sinoatrial node, the heart's pacemaker, and is transmitted partially by Perkinje fibers.