Lesson One : Activities and Quizzes
Activity 7: Generation of an electric field by a changing magnetic fieldRequired materials: A long bar magnet, 4 ft. of copper wire and a small light emitting diode (LED).
Procedure: Take the long piece of wire and wrap it into a coil. Make the diameter of the coil small, but also large enough that the magnet may be easily inserted and removed. Be sure that both ends of the wire are free and you have plenty of room to connect the LED. Lay the coil on its side and connect the two ends of the wire to the LED. Take the magnet and thrust it into the center of the coil. The LED should blink on. Quickly remove the magnet, and the LED should blink on again. Note that current is generated only when the magnetic field of the magnet is changing (that is, being rapidly inserted or removed).