please help answer this follow question solve a-b

A long solenoid has inside a coil of fine wire coaxial with it. The inside coil has Nj turns, the outside solenoid has No turns per meter. r R The current in the solenoid is given by 1 =lo (1 - e -t/T) a) What is the induced emf at t = 0? b) If lo = 30 A, T = 0.63 5, N2 = 430 turns/m, r = 25 cm, N1 = 250 turns, and R = 5 cm, what is the magnitude of the induced emf at time t = 0