Two solenoids are nested coaxially such that their magnetic field point in opposite directions. Treat the solenoids as ideal. The outer one has a radius of 20 mm, and the radius of the of the inner solenoid is 10 mm. The length, number of turns, and current of the outer solenoid are, respectively, 20.5 cm, 517 turns, and 5.37. For the inner solenoid the corresponding quantities are 18.7 cm, 305 turns, and 1.65 A. The elementary charge is 1.602 x 10^-19 C, the mass of the proton is 1.673 x 10^-27 kg, and the vacuum permeability constant has the value