Electric potential across a cell membrane in a typical living cell, the electric potential inside the cell is 7.2×10−2 v lower than the electric potential outside the cell. the thickness of the cell membrane is 0.11 μm . you may want to review (pages 696 - 700) . part a what is the direction of the electric field within the cell membrane? what is the direction of the electric field within the cell membrane? outward across the cell membrane inward across the cell membrane tangentially to the cell membrane