28 בדצמבר 2006 בשעה 0:00 #8998
תגובה
ilanit siton
חבר

As a simple example, a two wire 500 MW transmission line at 500 kV draws; 500 amperes in opposing directions in the two wires. From Ampere”s law a; single wire of 500 A produces a field of 33 mG at a distance of 30 m. If; two opposing currents of 500 A are separated by 4 meters, the field will; be 4.4 mG (in the plane of the wires). By reducing the separation to 1; m, the field falls to 1.1 mG. At a doubled distance of 60 m, the field; from the single conductor is 17 mG and the fields from the paired; conductors are 1.1 mG for a 4-meter separation and 0.3 mG for 1-meter; separation. Motor and appliance electrical coils produce either magnetic; dipole or quadrupole fields that diminish as the inverse square or cube; of the distance, respectively. Average fields at a distance of 30 cm; are: color television (7 mG), microwave (4 mG), analog clocks (15 mG),; electric razors (20 mG, 100 mG at 15 cm) and hair driers (1 mG, 300 mG at; 15 cm).