5H60.10 - Einstein De Haas Effect
Demonstrate the spin angular momentum of electrons.
Use the dedicated Einstein de-Haas setup (only use Coulomb law setup as alternative).
**Be sure to remove the foam inserts when running the appartus, but be sure to replace the foam inserts whenever the cart is in motion.**
Connect the solenoid to the output of the Samson SX2400 amplifier. Make sure the amplify is on a single channel (not bridged). Connect the arbitrary function generator to the input of the amplifier and set the frequency to the resonant frequency of the torsion suspension (~1.8 Hz). Turn the amplifier output to about 10 'o-clock on the knob. Allow to run for about a minute for the resonant effect to become visible.
**Be sure to inform instructors not to turn up the amplitude above the 10 o-clock setting or it will overheat the solenoid**
Set the frequency generator to 1.8 Hz. Turn up the amplifier to the 10 o-clock point on the knob. Wait about a minute for the system to become resonant.
Discovered in 1915, the Einstein-De Hass effect is a relationship between magnetism, angular momentum, and the spin of electrons. The experimental setup consists of a ferromagnetic body that is suspended inside a solenoid by very thin wires. A mechanical rotation of the ferromagnetic body can be achieved slowly over time when an AC current is applied through the solenoid at a resonant frequency. The mechanical rotation results from the conservation of angular momentum. When the electrons magnetic moments align with the applied field, their angular momentum changes producing a torque on the ferromagnetic body. This is a beautiful experiment describing a connection between classical and quantum physics.