5K40.80 Hand Crank Flashlight

Concepts

Electromagnetic induction, conservation of energy, Faraday's law

Overview

The flywheel inside the flashlight spins when the handle is squeezed. Since the flywheel is mounted on a magnet, the rotation of the flywheel creates a change in magnetic flux. This generates an EMF that illuminates a light bulb inside the flashlight. Note: the apparatus is small but the light is visible from the back of a large lecture hall when the room lights are dimmed.

Details

Equipment

  • [1] Hand crank flashlight (a flashlight containing a coil and a rotating magnet)

Script

  1. Squeeze the handle repeatedly until light bulb is turned on.

 

Additional Resources

References

  • PIRA 5K40.80

Disclaimer

  • Don't attempt this at home!

Last revised

  • 2018

Technicals

Related AV

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.