A solenoid with a length of 20 cm and a radius of 5 cm consists of 400 turns and carries a current of 12 A. If z = 0 represents the midpoint of the solenoid, generate a plot for |H(z)| as a function of z along the axis of the solenoid for the range –20 cm ≤ z ≤ 20 cm in 1 cm steps.