5K10.48 - Current-Coupled Oscillators
Demonstrate the effect of currents induced by a mechanically oscillating magnetic field in a coil.
A hand magnet is suspended by a spring so that it is half-inside a solenoid. When the mass(magnet)/spring starts to oscillate, the magnet goes inside the solenoid and induces a current which is transferred to the other solenoid, producing a magnetic field which causes the other magnet/mass/spring assembly to go into oscillation. The magnets will continue to oscillate for several minutes. When the solenoid is shorted out, the oscillations will stop in a matter of seconds. When two solenoids are connected, each with a spring and magnet suspended above, the two setups become a coupled harmonic oscillator. When both of the north poles of the magnets are attached to the springs, the two magnets will oscillate in phase with each other. When one magnet is switched to the south pole, the two setups will oscillate out of phase. The same effect can be accomplished by switching the wires or flipping the orientation of one solenoid. Make sure that the magnet/solenoid assemblies are separated by about three feet. I
Conservation of Energy