Physicists are finding that the skills they have learned in their training may be applied to areas beyond traditional physics topics. One such field is that of geophysics. This paper presents the electrical resistivity component of an undergraduate geophysics course at Radford University. It is taught from a physics perspective, yet the application of the theory to the real world is the overriding goal. The concepts involved in electrical resistivity studies are first discussed in a general sense, and then they are studied through the application of the relevant electromagnetic theory. Since geology majors comprise the bulk of the students in this class, the math used is only that which is typically required of geology majors. The final results are given in a form that practicing geophysicists may use in the field. A method is presented for constructing an inexpensive apparatus for measuring electrical resistivity in both a tabletop laboratory setting and in the field. This apparatus is truly ''plug and play'' since its assembly and use requires only the most basic knowledge of electronics. This apparatus is tested in a tabletop laboratory setting as well as in two field surveys.

The DeWitt-Schwinger proper time point-splitting procedure is applied to a massive complex scalar field with arbitrary curvature coupling interacting with a classical electromagnetic field in a general curved spacetime. The scalar field current is found to have a linear divergence. The presence of the external background gauge field is found to modify the stress-energy tensor results of Christensen for the neutral scalar field by adding terms of the form (eF ) 2 to the logarithmic counterterms. These results are shown to be expected from an analysis of the degree of divergence of scalar quantum electrodynamics.

A simple model is constructed to illustrate candidate interior geometries for charged spherical black holes. The new feature of this model is the explicit consideration of the evolution of the electromagnetic field and charge distribution in the black-hole interior. The model is constructed by joining the Reissner-Nordstrom and Schwarzschild geometries along a spacelike hypersurface at a constant radius lying between the inner and outer horizon radii of the Reissner-Nordstrom geometry. This model represents an idealization in which the Schwinger pair creation rate is approximated as zero below a critical electric field value Eo and as infinity above the critical field value. The spacelike hypersurface on which the geometries are joined represents a sheet of current caused by the created charged pairs. This current eliminates the interior electromagnetic field, resulting in a final state for the black-hole interior which contains no Cauchy horizons, naked singularities, or "tunnels to elsewhere." PACS numberk): 97.60.Lf, 04.20.Jb

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By utilizing the iterative capabilities of spreadsheets, students who do not have a programming background may obtain numerical solutions to complex equations. This paper discusses two examples of spreadsheet programming. One models the structure of a planet using a set of ordinary differential equations depending on the radius of the planet. The other involves coupled partial differential equations in a model of a planetary atmosphere. The results of the planetary models are compared to the values for Earth and Neptune. The results of the atmospheric model are compared to values for Earth’s atmosphere.