# Homework Help: Current induced magnetic field

1. Mar 12, 2012

### get_physical

1. The problem statement
I'm doing a stimulation. Here is a picture of it.
http://desmond.imageshack.us/Himg267/scaled.php?server=267&filename=22904502.jpg&res=medium [Broken]
The questions asks: when moving the voltage slider on the battery and dragging it all the way from right to left, what happens?
- compass flips or stays the same.
- magnetic field flips direction or stays the same.
- current flows in the opposite direction or in the same direction.

3. The attempt at a solution

I know that current stays the same and that the compass flips.
Since the current stays the same, does that mean the magnetic field direction stays the same? When I move it, it seems like the magnetic field lines above and below the current in the wires flips, while the area inside the coil of wire stays the same.

Last edited by a moderator: May 5, 2017
2. Mar 12, 2012

### Staff: Mentor

Hi get_physical! Why do you believe the coil current stays the same when you reduce the voltage across the coil?

Perhaps I haven't appreciated a marvel of simulated batteries: does one end of the slider deliver positive voltage, and when slid all the way to the other end deliver negative voltage??

3. Mar 12, 2012

### Staff: Mentor

I'm wondering how you know what seems to be happening inside the coil--you can't see any field arrows in there, can you?

4. Mar 12, 2012

### get_physical

Thanks so much for your reply. I didn't know it was the wrong slider that i was sliding.
Now i know that the current changes and that the compass flips. So does the magnetic field also flip direction? I'm guessing yes, but not totally sure.