Pre-class Exercise #8

The animation shows a top view of three wires and a galvanometer.  A fourth wire closes the loop when the animation is initiated with the start link below.  There is a constant magnetic field passing through these wires.  Determine the direction of this magnetic field by click-dragging the fourth wire back and forth and observing the current direction and galvanometer reading.  Note that current flowing into the + terminal, i.e., counterclockwise, will deflect the meter to the right.  Also note that the current arrow specifies the direction of current flow in the top branch of the loop.   Start.

Hint: Moving the fourth wire changes the magnetic flux through the loop.  The direction of current flow indicates the direction of the induced magnetic field.  How does the induced field depend on the change in flux?


  Your Name:

  Your Answer:

 A.  Toward the top.  That is, out of the computer monitor.

 B.  Toward the bottom.  That is, into the computer monitor.


This Physlet was created by Mario Belloni and Wolfgang Christian.