The figure is a sectional area of a long coaxial cable. The radius of its metal strands are R1 = 3 mm, R2 = 4mm, r = 2 mm I1 = 15A, I2 = 5 A. Since the currents flow in opposite directions, to construct a graph of the scale in the magnetic field on the distance from the axis cable. Determine the magnetic energy stored between the metal conductors of the cable per unit length.

Detailed solution shorthand terms, formulas, laws used in the decision, the withdrawal of the calculation formula and the response.
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