# Electric field of a cell

1. Feb 3, 2009

### nic4birds

1. The problem statement, all variables and given/known data
The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. Assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.31 x 10-6 C/m2. (a) What is the magnitude of the electric field within the cell membrane? (b) Find the magnitude of the electric force that would be exerted on a potassium ion (K+; charge = +e) placed inside the membrane.

2. Relevant equations
E=charge density/Eo
F=(electric field)(Charge)
E=q/(Eo)A

2. Feb 3, 2009

### Hootenanny

Staff Emeritus
You seem to have missed out section three of the template: Attempted Solution...

3. Feb 3, 2009

### nic4birds

for this problem i do not know how to start it, i believe that the 7.31 value is the charge density but i do not know what the other value Eo would be. once i can solve for the first part i will be able to calculate for the magnitude of the electric force

4. Feb 3, 2009

### Hootenanny

Staff Emeritus
Eo or ε0 is the permitivity of free space, which is a constant one has to look up.

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