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this is the convention given in my textbook

This figure is to explain angle of dip of a magnetic needle.

I think the direction of the magnetic field taken is itself wrong. In the given figure the direction of magnetic field of earth is taken to be B and H and Z are its respective horizontal and vertical components. Now, according to this direction of the magnetic field. The North Pole of the needle of the magnetic compass will actually point towards the geographic South Pole which I have not heard of happening (though I could be unaware of such occurrence). I want to verify if this figure is actually correct. This figure is from my high school textbook. According to the convention given in textbook north magnetic pole is near the geographic North Pole and south magnetic pole is near the south geographic pole. The field lines emerge from the south magnetic pole and enter the north magnetic pole to form closed loops.

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  • $\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$
    – Community Bot
    Commented May 23, 2022 at 10:40
  • $\begingroup$ The diagram you've given doesn't specify what $N_m$ is - if it's magnetic north it's wrong, if it's the north pole of the magnetic field (which is actually at the south pole geographically) then it's fine $\endgroup$
    – sqek
    Commented May 23, 2022 at 12:47
  • $\begingroup$ According to the correct convention, 𝑁𝑚 is actually South Pole of the earth magnet. Magnetic field lines are entering through 𝑁𝑚. $\endgroup$
    – Gaurav Aggarwal
    Commented May 23, 2022 at 14:48
  • $\begingroup$ @sqek Do you mean the figure is wrong if 𝑁𝑚 is South Pole of the Earth magnet? $\endgroup$
    – Gaurav Aggarwal
    Commented May 23, 2022 at 14:52
  • $\begingroup$ @GauravAggarwal In the diagram, $B$ is pointing away from $N_m$, so $N_m$ is the North pole of the earth magnet, at the geographic South as far as I can tell $\endgroup$
    – sqek
    Commented May 23, 2022 at 16:14

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The poles of the magnet Earth are as in the figure included in this link: https://www.wtamu.edu/~cbaird/sq/2013/11/15/why-does-a-magnetic-compass-point-to-the-geographic-north-pole/ The South of the Earth magnet is near the geografic North and vice-versa. By convention, the end of the compass pointing (approximatelly) towards the geografic North was labeled "North". So, being attracted by the South of another magnet (and repelled by the North) it must point towards a real magnetic South pole. Unfortunatelly, you can see many web pages labeling the pole of the magnet Earth near the geografic North as "magnetic North". This is either uisng a different convention than the one in physics or is just ignorance of physics, expecially when they show the actual magnet, modelling Earth, with the North pole in the Arctic zone. Too bad that the figure is from a physics textbook. Maybe you should look for a different book. Look here, slide no 6, for the image in a decent book: https://web.njit.edu/~tyson/P122-ECE_Lecture8_Ch27.pdf

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