Microwave ovens cook food by emitting microwaves, which are high-frequency electromagnetic waves. These waves are directed into the oven cavity and this microwaves cause the molecules in food to vibrate, which in turn creates friction resulting in heat. The heat produced by the molecular friction cooks the food from the inside out. Since, the surrounding air does not absorb this microwaves, the cooking and baking time is greatly reduced compared to other types of ovens.
Microwave ovens cook different types of foods at different rates. The amount of microwave energy available to heat and cook food is called as the power output of the microwave oven. It is usually described in Watts e.g. 700 Watt power output. The input is the total amount of watts used by the appliance to generate the microwave energy. The input is always more than the output. Microwave ovens vary in the power of the magnetron, which generates the microwaves. Large ovens and midsize ovens are rated as 1,650 watts to 850 watts and compact ovens are rated as600 to 800 watts. A higher wattage may heat food more quickly. A commercial model, which is used for fast food service, or dealing with large number of people often has a higher wattage than domestic models and is built with the appropriate components to meet these requirements.
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