GEOPH424 Final: GEOPHYS 424 UofA Final Exams 2012 424 Final
Document Summary
Monday april 23rd 2012, 9 am noon. Cell phones and all other electronic devices must be switched off and stored. All questions must be directed to the invigilator. A separate 2 page formula sheet will be distributed. Question 1 : resistivity of rocks (total = 16 points) A crystalline rock contains graphite in aligned cracks. The graphite has a resistivity of g and the rock matrix has a resistivity of r. Consider a cube that is 1 m x 1m x 1m. (1a) derive an equation for the resistance of the cube when electric current flows parallel to the cracks. Consider 0 < v < 1 (3 points) (1b) derive an equation for the resistance of the cube when electric current flows normal to the cracks. Consider 0 < v < 1 (3 points) (1c) sketch these resistance values on a graph for the range 0 < v < 1.
