In reading about magnetic resonance imaging, I was surprised to learn that the coil/antenna used to send a radiofrequency pulse into the person being scanned is not a coil/antenna at one end of the person, but a large coil actually wrapped around the person.
I know how alternating current...
I understand how a 180 degree pulse would cause a magnetization vector aligned with the external magnetic field to rotate into anti-parallel alignment with the external magnetic field.
But using a 181 degree pulse rather than a 180 degree pulse, ie adding MORE energy, how do we get a...
To make sure I am following correctly... The component of the magnetization vector along the z axis represents the balance between spin up and spin down protons. A vector pointing in the +z direction represents an excess of low energy protons, and a vector pointing in the -z direction represents...
I've been reading about nuclear magnetic resonance, and one aspect is bothering me. (I haven't studied quantum physics yet.)
Quantum mechanically, the proton has only 2 energy states: spin +1/2 spin and spin -1/2. In NMR, a pulse of electromagnetism is applied to alter the orientation of the...
By "carrier particle" I didn't mean the medium in which the wave travels (air, water, vacuum etc.) but the way one charged particle learns that there is another charged particle nearby, and then acts according to the electric field equation.
Something must travel from the first particle to...
Text books talk about EM waves from moving charges, but don't mention EM waves radiating from a standing ie. not moving charge?
I would think that for one standing charge to exert a force on a second standing charge, there must be a carrier particle/wave. Is this not an EM wave?
Thanks!
Jon