|MadSci Network: Engineering|
I do not think that it is possible to cause microwaves to be produced just by holding a magnet near the waveguide or magnetron. Typically, a fairly large amount of power is needed to produce microwave energy. Additionally, using a magnet is not a reliable method to determine if something is a metal. Conventional magnets are attracted to iron. There are pure metals that do not contain iron; for example -- copper and aluminum. Alloy metals, such as brass (copper and zinc) or bronze (copper and tin) also do not contain iron.
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