A steel ring of mean circumference 63 cm and cross-sectional area 6 cm² is uniformly wound with a coil of 500 turns. Calculate (1) the current required producing flux of 0.45 × 10⁻³ Wb in the steel ring, and (ii) the current required for same amount of flux when a saw cut of 1 mm width is made in the ring. The BH curve table is given as:

H AT/m 626 646 666 686 706
B wb/m² 0.6 072 0.750 0785 0815