A cell membrane consists of an inner and outer wall separated by a distance of approximately 10 nm. Assume that the walls act like a parallel plate capacitor, each with a charge density of 10^−5C/m^2, and the outer wall is positively charged. Although unrealistic, assume that the space between cell walls is filled with air.
What is the magnitude of the electric field between the membranes? Answer: 1*10^6 N/C
What is the magnitude of the force on a K+ ion between the cell walls? Answer: 2*10^-13 N
What is the potential difference between the cell walls? Answer: 1*10^-2 V
Question : If released from the inner wall, what would be the kinetic energy of a 7 fC charge at the outer wall? 1fC = 10^−15C.
KE = q*Delta(v)
The Attempt at a Solution
I have solved each of the other parts of this question. I found that Delta V was 1×10^−2V. The question states that 1fC is 10^-15 C. I plugged in for KE = (7*10^-15)(0.01V), and keep getting 7*10^-17. However the answer is 8*10^-17. Can anyone catch my mistake, or am i using the wrong formula?