The magnetic circuit shown in Fig. P.2.8 has a coil of 500 turns wound on the central limb which has an air-gap of 1 mm. The magnetic path from A to B via each outer limb is 100 cm and via the central limb 25 cm (airgap length excluded). The cross-sectional area of the central limb is 5 cm × 3 cm and that each outer limb is 2.5 cm × 3 cm. A current of 0.5 A in the coil produces an air-gap flux of 0.35 mWb. Find the relative permeability of the medium.
