One solenoid is centered inside another. The outer one has a length of 47.0cm and contains 6800 coils, while the coaxial inner solenoid is 5.00cm long and 0.120cm in diameter and contains 15.0 coils. The current in the outer solenoid is changing at 37.5A/s.
a) What is the mutual inductance of these solenoids?
b) Find the emf induced in the inner solenoid?