Magnetism scenario: magnet attracted to iron wall

[sgstudent]

Hi when a good former explained a theory, I didn't understand this very well. So I'll check it out again. Sorry for the many posts my me and thanks!

When a magnet is placed vertically to an iron wall it gets attracted.(meaning the north and south poles are in contact with the iron wall). Since it gets attracted to it and sticks to it does it mean that the magnetic field line leaves the iron wall when it 'sees' the other end of the pole? Because if the magnetic field continues on, then there won't be any north/south pole in the area and there song be any attraction.

Secondly, for any attraction to happen are the two conditions- must have pole opposite to the magnet facing you. Must be within a magnetic field. If one of these conditions are not met, then the thing will not be attracted. Is this right? I deduced it due to the idea that if u put a thin iron sheet in between a bar magnet and some tack the tack won't be attracted but the iron bar will be attracted to the magnet. I thinkso because even though a pole is facing the tack, due to magnetic shielding little magnetic field lines will pass through it. While the magnet attracts the iron sheet as there is both a magnetic field and av pole there.

Thanks for the help and please try to answer both questions. Thanks.

 

[Vailanor]

Yes, the magnetic field does leave the iron wall when it “sees” the other end of the pole. It is important to note that the magnetic field lines form a closed loop, meaning the field lines will enter the magnet at one pole and then exit the magnet at the other pole. This is why there is still an attraction when one pole is facing the iron wall and the other pole is facing away. The two conditions for attraction are that there must be a pole opposite to the magnet facing you, and that both objects must be within a magnetic field. If either of these conditions is not met, then there will not be any attraction. This is why placing a thin iron sheet between a bar magnet and some tack will prevent the tack from being attracted. The iron sheet blocks the magnetic field, so the tack is no longer within a magnetic field and thus the attraction is not possible.