3 ms·

> The transmitter converts electricity into radio frequencies, then beams the energy to nearby devices outfitted with a corresponding receiver. Just curious, a

• klodolph 9y ago
  Radio waves have been extensively studied for over 100 years, and there have been numerous studies trying to ascertain if they cause health problems in humans or other animals. "Radiation" is a bit of a scary word, the general public thinks of nuclear radiation. Even though radio waves can be called radiation they cannot cause harm in the same way that UV radiation causes cancer, for example. Radio waves can heat things up, and can even cause burns, but you'd need to do something incredibly stupid like disassemble your microwave, or stand in front of a primary radar dish. By comparison, the word "radiation" is often used to refer to ionizing radiation which can destroy molecules in your body, even at low power. The battery charging works because the antennas are very efficient at picking up radio waves of a specific frequency, unlike humans, which do not make very good antennas. I am personally skeptical about the power efficiency of wireless battery charging but radio waves are fairly benign to those of us made out of meat.
• empraptor 9y ago
  EDIT: I didn't consider dielectric heating (https://en.wikipedia.org/wiki/Dielectric_heating https://en.wikipedia.org/wiki/Dielectric_heating). Seeing as how microwave ovens have 500W rating on the low end, I assume heat generated by 10W source can be dissipated fast enough that proteins don't get denatured even if it's directed at a small area of the body. Most energetic photon in radio frequencies has wavelength of 1mm and energy of 0.00124eV (http://www.photonics.byu.edu/fwnomograph.phtml http://www.photonics.byu.edu/fwnomograph.phtml) I think. Would just pass through a single cell as cell is much smaller than the wavelength. And 0.0012eV is really small amount of energy. "Van der Waals bonds are weak bonds with a dissociation energy of about 0.01 eV" (http://lamp.tu-graz.ac.at/~hadley/ss1/crystalbinding/bonds/bonds.php http://lamp.tu-graz.ac.at/~hadley/ss1/crystalbinding/bonds/b...) I wouldn't expect it to do anything cellular/molecular level. Not really a biology person so don't know if there's some effect on aggregate of cells on the millimeter level that could be harmful. Human body's electrical resistance inside is high and through skin is higher so I don't expect much effect on that scale either?
  • tudorw 9y ago
    I'm no biology person either, but in terms of photons, I do find these interesting; 'Biological tissues typically produce an observed radiant emittance in the visible and ultraviolet frequencies ranging from 10−17 to 10−23 W/cm2 (approx 1-1000 photons/cm2/second).[1] This low level of light has a much weaker intensity than the visible light produced by bioluminescence, but biophotons are detectable above the background of thermal radiation that is emitted by tissues at their normal temperature. While detection of biophotons has been reported by several groups,[2][3][4] hypotheses that such biophotons indicate the state of biological tissues and facilitate a form of cellular communication are still under investigation,[5][6] and claims that biophotons are responsible for physical healing are unsupported. Alexander Gurwitsch, who discovered the existence of biophotons, was awarded the Stalin Prize in 1941 for his mitogenic radiation work.[7]' https://en.wikipedia.org/wiki/Biophoton https://en.wikipedia.org/wiki/Biophoton