Hey I'm new here so I don't know if this is the right forum, but from what I could see this was the most relevant. 1. The problem statement, all variables and given/known data A long solenoid with 50 turns per cm carries a current of 0.2 A. The solenoid is filled with an iron alloy. The magnetic field B inside the iron alloy is measured to be 1.58 T acting parallel to the axis of the solenoid. Calculate the: i) size of the applied field Bapp; ii) size of the magnetization M in the iron alloy; 2. Relevant equations This is my problem really as I don't know so far I've been using the magnetic field of a solenoid = (N/L) *I*μ0, however I don't know if this correct or if it needs the permeability of the core to produce an accurate value. I've also been using Bt= Bapp+μ0*M rearranged to M= (Bt-Bapp)/μ0 to answer the second question. 3. The attempt at a solution Well this is just plugging numbers into the equations so I'm confident that I haven't done anything wrong here. Assuming the solenoid field is Bapp, Bapp=5000*0.2*1.3×10−6 = 0.0013. Putting that into the rearranged equation. M = (1.58 - 0.0013)/1.3×10−6 = 1.2106. My problem here is those values seem very small and ridiculously large respectively, have I done something wrong or am looking for errors where there are none?