N=300 turns of this wire are uniformly wound on a permanent magnet shaped as a cylinder whose length is equal to l=15cm. When a current I=3.0A was passed through the wiring the field outside the magnet disappeared. Find the coercive force Hc of the material from which the magnet was manufactured.
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Updated on : 2022-09-05
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Correct option is A)
The coercive force Hc is just the magnetic field within the cylinder. This is by circulation theorem, Hc=lNI=6kA/m
(from ∮H⋅dr=I, total current, considering a rectangular contour.)