I stumbled upon this question and I can’t seem to figure it out. I think you have to use the right hand rule, but it doesn’t get me the right answer. The question is something along the lines of:
In which direction does the current flow in a wire moving from the northern hemisphere down towards the southern hemisphere? The wire is oriented east to west.
So, the magnetic field in the northern hemisphere points downward, and the wire is moving south, so also down. I don’t see how I could apply the right hand rule to this, since my thumb and fingers would both point downward. Apparently the answer is east, and I could get that if the magnetic field moved down into the earth, and the wire moved south along the earth. Is this where my mistake it? I always thought that the magnetic field moved down from the north to south, not necessarily into the earth.
Best Answer
You might be able to figure this out by looking at the following picture (source: http://www.unc.edu/depts/oceanweb/turtles/geomag.gif):
As you can see, the field lines point into the earth.