help finding the electric feild strength in a uniform E-field

1. The problem statement, all variables and given/known data



The voltage across a membrane forming a cell wall is 78.7 mV and the membrane is 8.52 nm thick. What is the electric field strength? (The value is surprisingly large, but correct.) You may assume a uniform E-field.





2. Relevant equations



E=-Vd



3. The attempt at a solution



E=-(.00787V(8.52e-9m)) = 7.9e-11 V



i dont understand why this is wrong?

1. The problem statement, all variables and given/known data







2. Relevant equations







3. The attempt at a solution