XPost: sci.electronics.design   
   From: bill.sloman@ieee.org   
      
   On 20/02/2026 2:49 am, Ross Finlayson wrote:   
   > On 02/19/2026 04:39 AM, Bill Sloman wrote:   
   >> On 19/02/2026 9:56 pm, J. J. Lodder wrote:   
   >>> Bill Sloman  wrote:   
   >>>   
   >>>> On 19/02/2026 7:49 am, Ross Finlayson wrote:   
   >>>>> On 02/18/2026 12:43 PM, Python wrote:   
   >>>>>> Le 18/02/2026 à 20:13, Ross Finlayson a écrit :   
   >>>>>> ..   
   >>>>>>> and, you know, magnetic monopoles, is widely employed   
   >>>>>>> in medical imaging and the like.   
   >>>>>>   
   >>>>>> No.   
   >>>>>   
   >>>>> Resonance imaging (NMR) is a thoroughly different mechanism   
   >>>>> than Roentgen rays.   
   >>>>   
   >>>> But as the name implies, it's nuclei of the atoms involved that exhibit   
   >>>> the resonance. It's a remarkably low energy effect, and you need   
   >>>> remarkably high magnetic fields to get it to give you a detectable   
   >>>> signal.   
   >>>   
   >>> Nevertheless, it is easily demonstrated in the kitchen   
   >>> with some simple electronics.   
   >>   
   >> Sort of.   
   >>   
   >> https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance   
   >>   
   >> There are lots of different ways to exploit nuclear magnetic resonance.   
   >> The earth's magnetic field is high enough to let you devise experiments   
   >> that can demonstrate the effect on a kitchen table. Medical imaging   
   >> works a lot better with high fields. In 1979 I got to ask the EMI   
   >> Central Research NMR imaging development team why they weren't using   
   >> super-conducting magnets, and got told that you couldn't modulate the   
   >> field.   
   >>   
   >> The fact that you couldn't modulate the total number of flux lines   
   >> threading a super-conducting coil didn't mean what they thought it did   
   >> at that time.   
   >   
   > Here there's that Faraday rotation basically puts a spin on   
   > Maxwell equations that otherwise are crossing lines.   
   >   
   > I.e., there's an idea that all waves are spirals and all spirals   
   > are waves, with usual useful notions of wave mechanics as incomplete.   
      
   Radiation can be polarised, and the plane of polarisation can rotate   
   quite rapidly, in whichever sense you chose.   
      
   Faraday showed that a magnetic field can rotate the plane of   
   polarisation of radiation travelling through a birefringent material.   
      
   https://en.wikipedia.org/wiki/Faraday_effect   
      
   --   
   Bill Sloman, Sydney   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)