I have noticed that on the door to microwave ovens there is a metal gridded screen. Is the purpose of this screen to construct a Farraday cage so none of the radiation can escape? If so, does this make standing in front of the microwave perfectly safe?
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3Possible duplicate of How does the grid on the microwave oven window prevent microwave radiation from coming out? – StephenG - Help Ukraine Aug 04 '19 at 20:39
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2"Is it perfectly safe ?" is not really answerable. Safety is an engineering and health concept and they doesn't do "perfectly", They do say, e.g. "very unlikely to cause harm". My friend once put a tin of baked bins (unopened) in and after turning on the microwave the tin did explode, breaking the microwave door. So the message, kiddies, is that you're probably safe from the microwave but the microwave may not be safe from you. – StephenG - Help Ukraine Aug 04 '19 at 20:46
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@StephenG I agree "perfectly" was the wrong word choice but I think you could tell I was referring to the radiation and not exploding tins of beans – Joe Aug 04 '19 at 20:52
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Is the purpose of this screen to construct a Farraday cage so none of the radiation can escape?
The purpose of the screen is to allow persons to view the contents of the microwave oven. It allows visible light to pass through but not microwaves,
You are correct that the metal screen is a form of a Faraday cage. The the diameter of the openings, on the order of a few millimeters, is much less than the microwave wavelength of about 12 cm, so that they don't pass through.
If so, does this make standing in front of the microwave perfectly safe?
The purpose of the screen is not to make the microwave oven safe. As I said, its purpose is to allow viewing the oven contents. But the design of the screen (e.g.,size of openings) is such that it can serve its purpose and at the same time have the microwave oven meet safety standards (Federal and other) for microwave leakage.
Hope this helps.
BioPhysicist
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Bob D
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@Aaron Stevens. No problem with the edits. Thought you should know, however, I used the term "visible" with light because that's the part of light relevant to the purpose of the screen. Regards, – Bob D Aug 04 '19 at 23:11
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I didn't see you use the term "visible", so I put it in since microwaves are also light. – BioPhysicist Aug 04 '19 at 23:39