If you're seeing this message, it means we're having trouble loading external resources for Khan Academy.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.


As the current passes through a straight wire the magnetic field wraps around the wire in concentric circles.

If we point our thumb along the direction of current (I) flow, our fingers curl around in the direction of the magnetic field lines (B).


This means a loop of wire must create a magnetic field which flows through the loop and around the outside!


Challenge: Amplify & Measure

How could we increase the strength of the field through a loop as shown above?


How could we measure the force through the loop?