1.Opening And Closing Things
Older doors that were locked with big iron bolts can't be opened by controlling the electrical servo motors. Won't work cause there are no motors. To open these from the inside would require moving that big iron bold somehow and the best answer would be via a magnetic field. The first use of opening something magnetically was by the Fourth Doctor in Image of the Fendahl where the Doctor opened an old door using sound converted to magnetism to move the metallic pieces of a door lock. Both of these can be considered opening something and they do it with similar science. However, each controls a different facet of electromagnetism. By converting sound to electricity you can alter the magnetic field in the same way described earlier in how one can screw or unscrew a screw using sound. But instead of converting it to a spin current to produce torque, this controls the magnetic field to move the metallic object.
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