اوهم جو قانون

V، I ۽ R اوهم جي قانون جا پيرا ميٽر آهن.

اوهم جو قانون (Ohm's Law) ٻڌائي ٿو ته ,ڪنهن ڪنڊڪٽر جي ٻن نقطن جي وچ ۾ برقي ڪرنٽ، ڪنڊڪٽر جي ٻن نقطن تي لاڳو ٿيل وولٽيج جي سڌو متناسب (directly Proportional) هوندو آهي.

تناسب جي مستقل جي طور تي، مزاحمت (R) کي متعارف ڪرائڻ سان، اسان هن تعلق کي بيان ڪرڻ لاءِ استعمال ٿيندڙ ٽن رياضياتي مساواتن تي پهچون ٿا: $V=IR\quad {\text{or}}\quad I={\frac {V}{R}}\quad {\text{or}}\quad R={\frac {V}{I}}$

جتي "I" ڪنڊڪٽر ذريعي ڪرنٽ آهي، "V" ڪنڊڪٽر جي پار ماپيل وولٽيج آهي ۽ "R" ڪنڊڪٽر جي مزاحمت آهي. وڌيڪ خاص طور تي، اوهم جو قانون ٻڌائي ٿو ته هن تعلق ۾ R مستقل آهي، ڪرنٽ کان آزاد. جيڪڏهن مزاحمت مستقل نه آهي، ته پوئين مساوات کي اوهم جو قانون نه ٿو چئي سگهجي، پر ان کي اڃا تائين جامد/ڊي سي مزاحمت جي تعريف طور استعمال ڪري سگهجي ٿو. اوهم جو قانون هڪ تجرباتي تعلق آهي جيڪو ڪرنٽ جي شدت جي ڪيترن ئي حڪمن تي برقي طور تي چالڪ مواد جي وڏي اڪثريت جي چالکائي کي صحيح طور تي بيان ڪري ٿو. تنهن هوندي به ڪجهه مواد اوهم جي قانون جي تابعداري نٿا ڪن؛ انهن کي غير اوهمڪ سڏيو ويندو آهي.

قانون جو نالو جرمن فزڪسسٽ جارج اوهم جي نالي تي رکيو ويو هو، جنهن 1827 ۾ شايع ٿيل هڪ مقالي ۾، مختلف ڊيگهه جي تارن تي مشتمل سادي برقي سرڪٽ ذريعي لاڳو ٿيل وولٽيج ۽ ڪرنٽ جي ماپن کي بيان ڪيو. اوهم پنهنجي تجرباتي نتيجن کي مٿي ڏنل جديد شڪل کان ٿورو وڌيڪ پيچيده مساوات ذريعي بيان ڪيو.

فزڪس ۾، اصطلاح "اوهم جو قانون" قانون جي مختلف عام ڪرڻ لاءِ پڻ استعمال ڪيو ويندو آهي؛ مثال طور، برقي مقناطيسي ۽ مادي سائنس ۾ استعمال ٿيندڙ قانون جي ویکٹر فارم:

تفصيل

V, I, and R, the parameters of Ohm's law

سانچو:Electromagnetism

Ohm's law states that the electric current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance,^[1] one arrives at the three mathematical equations used to describe this relationship:^[2]

$V=IR\quad {\text{or}}\quad I={\frac {V}{R}}\quad {\text{or}}\quad R={\frac {V}{I}}$

where $I$ is the current through the conductor, V is the voltage measured across the conductor and R is the resistance of the conductor. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.^[3] If the resistance is not constant, the previous equation cannot be called Ohm's law, but it can still be used as a definition of static/DC resistance.^[4] Ohm's law is an empirical relation which accurately describes the conductivity of the vast majority of electrically conductive materials over many orders of magnitude of current. However some materials do not obey Ohm's law; these are called non-ohmic.

The law was named after the German physicist Georg 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 (see § History below).

In physics, the term Ohm's law is also used to refer to various generalizations of the law; for example the vector form of the law used in electromagnetics and material science:

$\mathbf {J} =\sigma \mathbf {E} ,$

where J is the current density at a given location in a resistive material, E is the electric field at that location, and σ (sigma) is a material-dependent parameter called the conductivity, defined as the inverse of resistivity ρ (rho). This reformulation of Ohm's law is due to Gustav Kirchhoff.^[5]

External links

Ohms Law Calculator

حوالا

↑ Consoliver, Earl L.; Mitchell, Grover I. (1920). Automotive Ignition Systems. McGraw-Hill. p. 4. https://archive.org/details/automotiveignit03divigoog.
↑ Millikan, Robert A.; Bishop, E. S. (1917). Elements of Electricity. American Technical Society. p. 54. https://archive.org/details/elementselectri00bishgoog.
↑ Heaviside, Oliver (1894). Electrical Papers. 1. Macmillan and Co. p. 283. ISBN 978-0-8218-2840-3. https://books.google.com/books?id=lKV-AAAAMAAJ&q=ohm's%20law%20constant%20ratio&pg=PA284.
↑ Young, Hugh; Freedman, Roger (2008). Sears and Zemansky's University Physics: With Modern Physics. 2 (12 ed.). Pearson. p. 853. ISBN 978-0-321-50121-9.
↑ Darrigol, Olivier (8 June 2000). Electrodynamics from Ampère to Einstein. Clarendon Press. p. 70. ISBN 9780198505945. .

[1] Consoliver, Earl L.; Mitchell, Grover I. (1920). Automotive Ignition Systems. McGraw-Hill. p. 4. https://archive.org/details/automotiveignit03divigoog.

[Millikan-2] Millikan, Robert A.; Bishop, E. S. (1917). Elements of Electricity. American Technical Society. p. 54. https://archive.org/details/elementselectri00bishgoog.

[3] Heaviside, Oliver (1894). Electrical Papers. 1. Macmillan and Co. p. 283. ISBN 978-0-8218-2840-3. https://books.google.com/books?id=lKV-AAAAMAAJ&q=ohm's%20law%20constant%20ratio&pg=PA284.

[4] Young, Hugh; Freedman, Roger (2008). Sears and Zemansky's University Physics: With Modern Physics. 2 (12 ed.). Pearson. p. 853. ISBN 978-0-321-50121-9.

[5] Darrigol, Olivier (8 June 2000). Electrodynamics from Ampère to Einstein. Clarendon Press. p. 70. ISBN 9780198505945. .

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