In an infinitely long current carrying wire (assuming zero resistance) say there is a definite current.(adsbygoogle = window.adsbygoogle || []).push({});

"Having current in it" means there is a flow of charge in it, which means if positive charge moves in one direction then negative charge moves in opposite direction. As we know that a charge in motion will have to produce a magnetic field which is precisely given by the famous "Biot-Savart 's Law" for a current carrying wire. But is it not this for a normal current carrying wire, that the magnetic field produced by positive charges is equal to that produced by negative charges.

So, when we derive the expression for magnetic field due to an infinitely long current carrying wire the magnitude is given by |B|=Uoi/2 (pi)d where d--->perpendicular distance of the point from the wire and i--->current in the wire.

And that's the expression derived without considering the fact that "in a current carrying wire both positive and negative charges flow" but "only positive charges flow"..there are many textbooks which say exactly the same.

So is this not a violation of obtaining result for something which is not the proclaimed one??

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warning..

the probability of this poster to contain irony is finite and maybe nearly one..(or even not)

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# Magnetic field due to a current carrying conductor is___?

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