Animal cells have a membrane that separates the interior of the cell from the outside environment. Typically, an electric potential difference exists between the inner and outer surfaces of the membrane.
Consider one such cell where the magnitude of the potential difference is 51 mV, and the outer surface of the membrane is at a higher potential than the inner surface. A sodium ion ($Na^+$) is initially just inside the cell membrane (initially at rest). How much work (in J) is required for a cell to eject the ion, so that it moves from the interior of the cell to the exterior?
