
Before doing the experiment with the current in the coil you can put your smartphone on a table directed to the south.
I got 41 microT. That's the local strenght of the magnetic field of the earth.
You have to substract it from the mesurements of the magnetic field in the coil.
I got a fairly good value for the magnetic permeability of air using a coil of 10 turns of wire on a plastic bottle.
I got 41 microT. That's the local strenght of the magnetic field of the earth.
You have to substract it from the mesurements of the magnetic field in the coil.
I got a fairly good value for the magnetic permeability of air using a coil of 10 turns of wire on a plastic bottle.