The magnitude of the Earth's magnetic field at either pole is approximately 7.99*10^-5 T. Suppose the field fades away, before its next reversal. Scouts, sailors, and conservative politicians around the world join together in a program to replace the field. One plan is to use a current loop around the equator, without relying on magnetization of any materials inside the Earth. Determine the current that would generate such a field if this plan were carried out. Tak the radius of the Earth as R_e = 6.37*10^6 m.
2007-11-30 21:17:52 · 1 answers · asked by andrew w 1 in Science & Mathematics ➔ Physics
From http://electron9.phys.utk.edu/phys136d/modules/m7/Ampere.htm can be shownn that
B=u I R^2/( 2[ R^2 + R^2]^3/2) or
B=u I R^2/( 2[ 2R^2]^3/2)
The question is what is permeability u of Earth. If you is known then
I= 2 B [ 2R^2]^3/2 / (u R^2)
I= 2 (7.99 E-5) [2 x (6.37E+6)^2]/( 2 [2x (6.37E+6)^2]^3/2)
I=8.87e-12 u
For vacuum u=1.2566371 E-6 N/A^2
2007-12-01 02:24:11 · answer #1 · answered by Edward 7 · 0⤊ 0⤋