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Electricity
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anuj
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Joined: 11 May 2009
Posts: 2592
24 Aug 2009 10:03:27 IST
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Ohm's law is not a fundamental law of nature. There are a number of commonly used circuit elements which do not obey this law.
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24 Aug 2009 11:18:36 IST
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ohm's law is V is directly proportional to I this law fails when:
1) V ceases to be proportional to I
2) The relation between V and I depends on the sign of V. In
other words, if I is the current for a certain V, then reversing
the direction of V keeping its magnitude fixed, does not
produce a current of the same magnitude as I in the opposite direction. Eg- diode
3) The relation between V and I is not unique, i.e., there is more than one value of V for the same current I. A material exhibiting such material is GaAs
For more in depths look at page no.101 NCERT Physics Part-1











