0

Is the magnetic field of a bar magnet influenced by the magnetic field of the earth. If so, will the magnetic field of bar magnet be different in a region where there’s no other magnetic field.

Qmechanic
  • 220,844
Jason
  • 1

2 Answers2

1

Yes it does. The magnetic field of the Earth applies a torque on the bar magnet so the magnetic field of a bar magnet in a region with the magnetic field of the Earth is present will be such that the north pole of the bar magnet is pointing towards the North (magnetic) Pole of the Earth. The device making use of this is called compass.

EDIT: To dispell possible confusion in response to the answer by @WAH, the magnetic fields do interact. The thing is that Maxwell's equations are only linear in the absence of charged matter. Once there are movable/polarizable/etc entities around, fields start talking to each other via those entities (charges, dipoles, quadrupoles, etc). This is most prominent in nonlinear optics, but the alignement of a dipole by an external field and subsequent modification of a total field is also strictly speaking a nonlinear electromagnetic effect.

John
  • 4,287
1

I actually disagree with @John's answer. Electromagnetism is linear. I.e. electromagnetic fields simply add to each other; the fields do not influence each other. See Why is classical electromagnetism linear?, Why is the Principle of Superposition true in EM? Does it hold more generally?, In classical physics (classical electrodynamics), why linearity of Maxwell's equations prevent interaction of electromagnetic waves?

The above said, I do agree with @John that Earth's magnetic field will yield a force on the bar magnet itself.

astronautgravity
  • 1,149