How does the reluctance of air in magnetic circuit compare with the resistance of air in electric circuit ?
Magnetic reluctance is analogous to electrical resistance, and is in units of At/W (Ampere turns per weber). There is an equivalent of Ohms law for magnetic circuits, where: Reluctance Magneto Motive Force / magnetic flux Where: Reluctance is in units of ampere turns per weber. MMF is in ampere turns. magnetic flux is in webers Reluctance is proportional to LengthOfPath / Permeability x CrossSectionalArea. The permeability of air is 1, the permeability of magnetic materials up to a few thousand. Using realistic figures of 0.04m path and area of 0.0001m^2. Air, 40 Iron, 0.16 Therefore air is 250 time the magnetic reluctance of iron. In the electrical case air is totally non conductive (except when it becomes ionised - breaks down). The resistance ratio between air and a metallic conductor approaches infinity.
Moving mass create electricity,mass in rest is magnetic field only.These have not in common.Any thing on your table have magnetic field and even a magnet until other moving mass not bend space about them and some of them start to moving.So moving mass can create the electricity due to magnetism just as induction create wire current.The table even can cross cable with 10kilo Volt but it can be noticed by only another moving mass! So it is hard question to understand.
