To study the variation of the electromotive force induced in a coil of wire as it is rotated in a uniform magnetic field produced by six permanent horseshoe magnets. By means of a spring-and-ratchet mechanism, the coil is rotated in ten-degree steps, five steps at a winding.  Capstone is used to graph the induced emf as a function of time for five ten-degree rotations.

The horseshoe magnets are mounted so that three magnets face the other three magnets with all six north poles on top and all six south poles on the bottom.  The magnetic flux travels from top to bottom through the centrally-mounted coil.  At 0-deg, the plane of the coil loop is at right angle to the field and maximum emf is induced.  At 90-deg, the plane of the coil loop is parallel to the field and minimum emf is induced.

Wind the coil up against the stop, setting the right stop to the 0 indicator point.  Click on RECORD, rock the ratchet release to go through five 10-deg rotations, and click on STOP.  You will see five pulses of diminishing amplitude.

Wind the coil up against the stop, setting the right stop to the 8 indicator point (this is 90-deg).  Click on RECORD, rock the ratchet release to go through five 10-deg rotations, and click on STOP.  You will see five pulses of increasing amplitude.