A toroid has 250 square windings carrying a current of \(3.0 \mathrm{~mA}\). Each side of each square winding is \(50 \mathrm{~mm}\) long, and the distance from the toroid center to the inner surface of the windings is \(120 \mathrm{~mm}\). What is the magnitude of the magnetic field \((a)\) at the center of any square winding, \((b)\) midway between the toroid center and the inner surface of the windings, and

(c) \(30 \mathrm{~mm}\) beyond the outer surface of the windings?