Problem 5.16 Two long coaxial solenoids each carry current I, but in opposite directions, as shown in Fig. 5.42. The inner solenoid (radius a) has n1 turns per unit length, and the outer one (radius b) has n2. Find B in each of the three regions:(1) inside the inner solenoid, (ii) between them, and (iii) outside both.

Fig: 1

Fig: 2