A very long straight wire carries a steady current of

PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Magnetostatics · Magnetostatics

Electricity, Magnetism and Electromagnetism, Ch Ampère's law, magnetic flux and the shape of the magnetic field

Problem

8.0\,\mathrm{A}

. Two circles are drawn concentric with the wire in a plane perpendicular to it, of radii

2.5\,\mathrm{cm}

and

5.0\,\mathrm{cm}

, each traversed in the sense in which the field points (fingers of the right hand curling with

\mathbf{B}

, thumb along the current). ((a)) Find the magnitude of

\mathbf{B}

on the circle of radius

2.5\,\mathrm{cm}

. ((b)) Find the magnitude of

\mathbf{B}

on the circle of radius

5.0\,\mathrm{cm}

. ((c)) Find the circulation

\oint \mathbf{B}\cdot d\mathbf{l}

round each circle (the same number for both). ((d)) Separately, a flat rectangular coil of

40

turns measuring

6.0\,\mathrm{cm}

4.0\,\mathrm{cm}

lies in a uniform field of

12\,\mathrm{mT}

with its normal at

55^\circ

to the field. Find the flux through one turn. ((e)) Find the flux linkage of that coil.