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| Biot and Savart's Law |
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| The Biot - Savart's law enables us to write the general results for the magnetic field due to an arbitrary current distribution or it is an experimental law predicted by Biot and Savart dealing with magnetic field strength at a point due to a small current element. |
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If AB represents a current element of a
conductor PQ carrying current I and  the position vector of
P from the current element AB (i.e., of length  ),
then the law states that magnetic field (dB) at P due to current element
depends on |
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| Combining we get, |
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| and is called permeability of free space. |
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| In the vector form, |
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| S.I. unit is 1 tesla or 1T. |
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| 2) If P lies on the conductor, dB = 0 |
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| 3) If q = 90o then dB is maximum |
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| 4) If q = 0o or q = 180o then dB is minimum |
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| Magnetic field due to a whole conductor is found by summing over all current elements. |
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| where the integration is taken over the entire conductor in which current I flows. |
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| Similarities |
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| 1) Both magnetic and electric field depend inversely on the distance between the source and the field point |
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| 2) Both are long-range forces |
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| 3) Principle of superposition applies to both fields as the fields are linearly related to the sources. |
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| Differences |
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