# Equation to describe the magnetic field sensed by a magnetometer

There are a magnetometer and a magnet placed at some distance D from it. We can assume that the magnet is a generic bar magnet. We can also assume that the Earth magnetic field is zero since the magnetic field of the magnet is stronger than the Earth magnetic field.

What is the equation that describes the magnetic field B? What is the equation if I assume a generic magnet? How the equation changes if I consider the Earth magnetic field?

• You can only consider the Earth's magnetic field to be negligible with respect to the magnet, NOT ZERO! So you have to consider the Earth's magnetic field under all circumstances. Sep 28, 2015 at 13:46
• Let's say that I save the readings when the magnet is not close to the magnetometer (i.e. the readings are not affected by it) and then subtract this value from the readings, then when the magnet is far from the magnetometer the readings will be zero. Under this hypotheses can I assume the Earth magnetic field is zero? If I do then is it possible to have an equation to model the current situation? Sep 28, 2015 at 15:17
• So I presume you intend to leave the Earth and go to outer space to carry out the experiment! For the Earth itself is a magnet. See this link ...kjmagnetics.com/blog.asp?p=earth-science Sep 28, 2015 at 15:21