Lag1989 problem number 17.46

600 turns of thin wire are evenly wound on an iron ring in one layer. The average diameter of the ring is 300 mm, its cross-sectional area is 6.00 cm². At what current strength I in the winding, the magnetic flux Ф through the cross section of the ring will be equal to 840 μWb. When solving the problem, use the curve shown in the figure.
According to the conditions of the above written problem, determine the magnetic permeability μ of iron.