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2عe mدمعا لمعهDeine W oh potes teal therence from Lehm's law. brauIgraph between LP and doctric |
| Answer» <p>Ohm's lawstates that thecurrentthrough aconductorbetween two points is directlyproportionalto thevoltageacross the two points. Introducing the constant of proportionality, theresistance,[1]one arrives at the usual mathematical equation that describes this relationship:[2]</p><p>{\displaystyle I={\frac {V}{R}},}</p><p>whereIis the current through the conductor in units ofamperes,Vis the voltage measuredacrossthe conductor in units ofvolts, andRis theresistanceof the conductor in units ofohms. More specifically, Ohm's law states that theRin this relation is constant, independent of the current.[3]Ohm's law is anempirical relationwhich accurately describes the conductivity of the vast majority ofelectrically conductive materialsover many orders of magnitude of current. However some materials do not obey Ohm's law, these are callednon-ohmic.</p><p>The law was named after the German physicistGeorg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. Ohm explained his experimental results by a slightly more complex equation than the modern form above (seeHistory).</p><p>In physics, the termOhm's lawis also used to refer to various generalizations of the law; for example thevectorform of the law used inelectromagneticsand material science:</p><p>{\displaystyle \mathbf {J} =\sigma \mathbf {E} ,}</p><p>whereJis thecurrent densityat a given location in a resistive material,Eis the electric field at that location, andσ(sigma) is a material-dependent parameter called theconductivity. This reformulation of Ohm's law is due toGustav Kirchhoff.[4]</p> | |