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Microwave Oven Wattage

  1. Apr 6, 2003 #1


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    Gold Member

    Just a quick question on microwave ovens if anyone knows it...

    If an oven is said to be 1000 Watts, does that mean it would use 1000 watts of electricity from the socket, or is that the rate at which food inside absorbs energy?

    If its the first, what would the rate of energy be that the food inside recieves?
  2. jcsd
  3. Apr 6, 2003 #2


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    Science Advisor

    Greetings !

    It's the first.
    Since the microwaves are almost completely
    "trapped" in the oven the food (and the plate :wink:)
    recieves most of it, after you consider the
    effectivness power losses of the oven of course.

    Live long and prosper.
  4. May 30, 2009 #3
    Sorry, the answer isn't correct. A 1000 watt microwave oven draws about 2000 watts from the wall - magnetrons @ 2.45 GHz are only about 50 % efficient. The "1000 watts" is a number arrived at using a international standard procedure - IEC 705 - that measures the heating rate of a 1 liter water sample at 10 decrees centigrade in a special glass dish. So, 1000 watts only refers to that circumstance - if I change the size or shape of the dish; use plastic instead of glass; a starting water temperature of other than 10 C, I'll get a different number. Also, that is an average taken over a number of ovens, so any of the ovens of that model may vary by +/- 15 % or more (850 to 1150 watts). The amount of energy absorbed by the food is very different and very complex. I published a paper on this many years ago and am giving another at a microwave conference in Washington DC in July.
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