This description applies to all questions 2.1-2.3. Two long…

This description applies to all questions 2.1-2.3. Two long coaxial solenoids each carry current I, but in opposite directions as shown in the figure below. The inner solenoid (radius a) has n­2 turns per unit length, and the outer one (radius b) has n1. The field B inside the inner coil is given by: