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A straight wire of mass 200 g and length 1.5 m carries a current of 2 A. It is suspended in mid-air by a uniform horizontal magnetic field B . What is the magnitude of the magnetic field? |
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Answer» Solution :we find that there is an upward FORCE F, of magnitude IlB,. For mid-air suspension, this must be balanced by the force due to gravity: MG= IlB `B = (mg)/(Il)` ` = (0.2 xx 9.8)/(2 xx 1.5) = 0.65 T` Note that it would have been sufficient to SPECIFY m/l, the MASS per unit length of the wire. The EARTH’s magnetic field is approximately `4 xx 10^(-5) T`T and we have ignored it. |
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