short note on microwave oven?

Microwave oven:
                              It is one of the great inventions of the 20th century. Microwave ovens are popular because they cook food quickly. They are also extremely efficient in their use of electricity because a microwave oven heats only the food - nothing else. A microwave oven uses microwaves to heat food. Microwaves are radio waves. In the case of microwave ovens, the commonly used radio wave frequency is roughly 2,500 megahertz (2.5 gigahertz). Radio waves in this frequency range are absorbed by water, fats and sugars. When they are absorbed they are converted directly into atomic motion - heat. Microwaves in this frequency range have another interesting property: they are not absorbed by most plastics, glass or ceramics. Metal reflects microwaves, that’s why metal pans do not work well in a microwave oven.