A small coil is introduced between the poles of an electromagnet so that its axis coincides with the magnetic field direction. The cross-sectional area of the coil is equal to S=3.0 mm2 , the number of turns is N=60 . When the coil turns through 180∘ about its diameter, a galvanometer connected to the coil indicates a charge q=4.5μC flowing through it. Find the magnetic induction magnitude between the poles, provided the total resistance of the electric circuit equals R=40Ω .