Using the approximations given in 61, find (a) the altitude above Earths surface where the magnitude of its magnetic field is 50.0% of the surface value at the same latitude; (b) the maximum magnitude of the magnetic field at the coremantle boundary, 2900 km below Earths surface; and the (c) magnitude and (d) inclination of Earths magnetic field at the north geographic pole. (e) Suggest why the values you calculated for (c) and (d) differ from measured values.

Lecture 6 Recall E = −∇V ∆V E = − ∆x U = qV Potential from a point charge q V = k r Potential from a distribution of charges 1 qi V = 4π r 0 i i Smooth distribution V = 1 qi= 1 ρdV 4π0 ri 4π0 r i...