Magnet Falling Through A Ring With Non-Zero Resistance

Associated Java Applet For These Videos/Animations

0.7 MEG QuickTime File

A magnet falls through a copper ring which has been immersed in liquid nitrogen. The magnet slows as it approaches the ring.

0.7 MEG QuickTime File

A close-up of the magnet falling through the copper ring.

1.4 MEG AVI File or 2.5 MEG QuickTime File.

An animation of the field lines of a magnet falling through a ring. When the magnet is above the ring the field line "pressure" perpendicular to the field slows the magnet as the field bunches up above the ring. When the magnet is below the ring the tension parallel to the field again slows the magnet. The current in the ring does not go to zero just as the magnet falls through the ring because of the inductance of the ring.

3.4 Meg QuickTime File.

Similar to the animation above, but we show only one field line, repeated many times in azimuth, to give a feel for the 3D nature of the field.

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