Astudent makes a short electromagnet by winding 580 turns of wire around a wooden cylinder of diameter d = 2.1 cm. the coil is connected to a battery producing a current of 5.1 a in the wire. (a) what is the magnitude of the magnetic dipole moment of this device? (b) at what axial distance z > > d will the magnetic field have the magnitude 4.1 µt (approximately one-tenth that of earth's magnetic field)?