A tightly wound solenoid 20 cm long has 400 turns and carries a current of 4A so that its axial field is in the z direction. Neglecting end effects, find B and Bsubapp at the center when (a) there is no core in the solenoid and (b) there is an iron core with a magnetization M=1.2 x 10 ^6A/m.
Taking the circulation of the magnetic field along the closed curve made of the axis of the solenoid and a curve outside, at which the magnetic field is negligible, we have
L*H = N*J (1)
where L=0.2 m is the length of the solenoid, N = 400 is the number of turns, J = 4A is the current and H is the H field which is ...
This solution calculates B and Bsubapp given two circumstances.