# Magnetic flux path

1. Sep 5, 2015

Hi, I was wondering about a simple example.take a coil wound on a solenoid, one side of the solenoid core is permanently attached to a permanent magnet S pole, the other end of the solenoid core is not attached to any magnet.
Now I take another magnet turn it with the N pole facing the solenoid and move it near and then again away from the solenoid, I get induced current in the solenoid coil.

my question is this, when the other magnet's N pole is not close or near the solenoid core does the solenoid core has magnetic flux in it from the S pole of the magnet that is attached to it's other side , or does flux only enter a certain material (low reluctance in this case) when the b field has an opposite pole to go into ?

2. Sep 5, 2015

### Drakkith

Staff Emeritus
Yes, the solenoid will have magnetic flux from the attached magnet pole passing through it even when the other magnet is nowhere nearby. These lines will eventually loop back around to the magnets north pole.

3. Sep 5, 2015

and the reason for that is probably because even without the other pole being there the field lines loop back to the other pole of the same magnet and they loop through the solenoid core because its reluctance to field is much less than that of air so the flux will always take that path no matter what right?

ok but then i have a question, does the flux being there in the core even without the other pole affect the coil sitting on the solenoid ? I assume no.I think only when the other pole is passed by the other side of the solenoid core only then the coil on it has induction correct?
so just by having one pole constantly attached doesnt ruin or change anything I can still move the other pole near the other side and get the same amount of induction that I would get when passing both poles of both magnets from each side ?

4. Sep 5, 2015

### Drakkith

Staff Emeritus
That I don't know. You'll certainly still get some amount of induction, but I don't now how having the magnet attached to the solenoid affects the induction generated by moving the 2nd magnet.