I'm studying magnetism from my textbook, and I have several doubts. 1. Magnetic flux in my textbook is defined as the number of magnetic field lines passing through a surface held perpendicular to the lines. However, the unit given is Weber- N.m/A How do 'no. of magnetic field lines' connect to a unit that has no apparent relation to 'lines'? 2. The textbook says that magnetic poles are formed due to an imbalance of north poles at one end and south poles at the other end. There is no other electron to neutralize them. Then why are magnetic poles not at the extreme ends of the magnet? The reason given is 'The positions of the poles are conjectured to be the points inside the magnet where the field lines appear to meet when extrapolated'. What does this mean? 3. I think the magnetic moment of a bar magnet is constant. Is this right? 4. According to what I read an electrons electrostatically repel each other but can magnetically attract each other. However I know that electromagnetism is a joint fundamental force. How do two same particles both attract AND repel each other with the same force? 5. And lastly, I've seen many formulae for induction along the axis of a bar magnet, solenoid, etc. Are these purely experimental or are the derivations of higher level(I'm reading the 11th grade book) and are proved later on? Thanks a lot.