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 S=3.0mm2 and the number of turns is N=60. When the coil turns through 180∘ about its diameter, a galvanometer connected to the coil indicates that a charge q=4.5μC flows through it. Find the magnetic induction between the poles, given that the total resistance of the circuit is R=40Ω.