The membrane that surrounds a certain type of living cell has a surface area of 5.0 10-9 m2 and a thickness of 1 10-8 m. Assume that the membrane behaves like a parallel plate capacitor and has a dielectric constant of 5.
(a) If the potential on the outer surface of the membrane is +70.0 mV greater than that on the inside surface, how much charge resides on the outer surface?
(b) If the charge in part (a) is due to K+ ions (charge +e), how many such ions are present on the outer surface?