What is the role of resonance in the heating process of a microwave oven?

[wasi-uz-zaman]

hi ,
i have studied that thing to be heated in microwave oven have water contents -due to resonance of microwave and frequency of water molecules - water molecules start oscillating with larger amplitude thus thing gets heated. But how just ceramic without any water contents get heated and how tungston filament bulb first get lighted and burst.
wasi

 

[Drakkith]

I didn't realize that resonance had anything to do with it. I thought it was simply that the microwaves were absorbed in the water or other material, heating it up.

 

[davenn]

I didn't realize that resonance had anything to do with it. I thought it was simply that the microwaves were absorbed in the water or other material, heating it up.

exactly ! :)

to quote the "beloved wiki"

Principles
For more details on this topic, see dielectric heating.

A microwave oven works by passing non-ionizing microwave radiation, usually at a frequency of 2.45 gigahertz (GHz)—a wavelength of 122 millimetres (4.80 in)—through the food. Microwave radiation is between common radio and infrared frequencies. Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a partial positive charge at one end and a partial negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field of the microwaves. Rotating molecules hit other molecules and put them into motion, thus dispersing energy. This energy, when dispersed as molecular vibration in solids and liquids (i.e., as both potential energy and kinetic energy of atoms), is heat.

cheers
Dave