# UBC PHAS Demonstration Room Catalog

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demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:locked_ring:start

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 demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:locked_ring:start [2019/02/14 23:33]127.0.0.1 external edit demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:locked_ring:start [2020/01/09 20:16]demoroom 2020/01/28 18:33 demoroom 2020/01/09 20:16 demoroom 2020/01/09 20:16 demoroom 2019/02/14 23:33 external edit 2020/01/28 18:33 demoroom 2020/01/09 20:16 demoroom 2020/01/09 20:16 demoroom 2019/02/14 23:33 external edit Next revision Both sides next revision Line 15: Line 15: - This is a demonstration for Faraday'​s and Lenz's Laws. The yoke magnet is supported by a ring of ball bearings between the white and red plate, which allows the magnet to spin in the vertical axis. As it spins, the non-magnetic brass ring appears locked, and spins with the motion of the magnet. ​   The change in the magnetic environment surrounding the ring causes an electromotive force to be induced in the ring (Faraday'​s Law). This EMF induces a current in the ring which generates a magnetic field that directly opposes this change in external magnetic field (Lenz'​s Law), thus conserving the magnetic flux through the ring.    Faraday'​s Law can be expressed as the following: ​  ​Voltage Induced= -N∆BA/​t ​ Where N is the number of turns of current allowing material (in this case, N=1, since it is just a ring, and not any sort of coil), B is the magnitude of the external Magnetic Field, and ∆A/t is the rate of change of area into or out of the magnetic field. + The yoke magnet is supported by a ring of ball bearings between the white and red plate, which allows the magnet to spin in the vertical axis. ===== Purpose ===== ===== Purpose ===== + This is a demonstration for Faraday'​s and Lenz's Laws. The ring moves to resist the change in flux that is caused by rotating the magnet. ===== Apparatus ===== ===== Apparatus ===== Line 28: Line 29: + Ensure that the ring is relatively centred within the yoke magnet by moving the thread and adjusting its length if necessary. ===== Notes ===== ===== Notes =====