Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Resonance in microwave oven

  1. Dec 29, 2011 #1
    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
     
  2. jcsd
  3. Dec 29, 2011 #2

    Drakkith

    User Avatar

    Staff: Mentor

    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.
     
  4. Jan 3, 2012 #3

    davenn

    User Avatar
    Science Advisor
    Gold Member

    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
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Resonance in microwave oven
  1. Microwave oven (Replies: 6)

  2. Microwave oven (Replies: 30)

Loading...