Question

Potassium ions (K+) move across a 7.0 -mm- thick cell membrane from the inside to the outside. The potential inside the cell is −70.0 mV, and the potential outside is zero. What is the change in the electrical potential energy ΔU electric of the potassium ions as they move across the membrane?

Answer 1

Explanation:

Relation between potential energy and charge is as follows.

           U = qV

or,    $\Delta U = q \times \Delta V$

                   = $1.6 \times 10^{-19} \times 70 \times 10^{-3}$

                   = $112 \times 10^{-22}$ J

or,                = $1.12 \times 10^{20} J$

Therefore, we can conclude that change in the electrical potential energy $\Delta U$ is $1.12 \times 10^{20} J$.