Electromagnetic induction
Spin the coil and let the changing magnetic flux drive a current.
When a coil rotates at constant speed in a uniform magnetic field, the magnetic flux through it varies periodically, producing an alternating EMF. When the flux is at its maximum, its rate of change is zero and so is the EMF; when the flux is zero, the magnitude of the EMF is greatest.
Induced EMF vs. time
Think about it
If the coil spins faster, how do the magnitude and frequency of the induced current change?
Both increase. The peak EMF NBAω is proportional to the angular velocity; the current reverses direction every half turn, so its frequency equals the coil's rotation frequency.
Model assumptions20-turn coil · circuit resistance 10 Ω · self-inductance ignored · driven at constant speed · side view of coil · flux per single turn
Data log
Set the parameters and click “Record data”. Record several rows with different parameters to plot their relationship and fit a straight line; pause and record at different times to study how a reading changes with time.