Science Questions

Is a microwave sealed?

Sat, 31st Mar 2007

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Question

John in Suffolk asked:

If you put your home phone number into a mobile phone and press enter, then put the mobile phone in a microwave, you can successfully make a connection and call your house phone. If the oven is supposed to protect you from the microwaves inside, how do they get out and make the phone call?

Answer

I have tried this at my girlfriend's house and it did actually cut out the phone connection, so the microwave oven does keep some of the microwaves coming out of the phone, inside the microwave (oven).  The frequency of the microwaves from a phone is not the same as the microwaves you use for cooking, if they were the same, then every time you turn the microwave on you wouldn't be able to talk on the phone, because you would get horrible interference.

In fact there is a gap (between the door and the main body of the oven), but the microwaves don't get out of this gap, because it's (the gap) tuned to be exactly a of the wave length of the microwaves.  As the phone works at a different frequency, some microwaves from your phone will get out of this gap.  So the oven will cut down the microwaves (from the phone) coming out of it but it won't cut it out completely because it's the wrong frequency.  On the other hand, the phone will also turn up it's power to make itself work!

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