Physics: Magnitude of the electric field in a cell membrane. And electric potential at unknown location B between two points.

Please review the attached two problems, write how to solve every step so I can learn how to do these. Please only use algebra based formulas.

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The inner and outer surfaces of a cell membrane carry a negative and positive charge, respectively. Because of these charges, a potential difference of about 0.065 V exists across the membrane. The thickness of the membrane is 8.9 x 10-9 m. What is the magnitude of the electric field in the membrane?

The potential at location A is 626 V. A positively charged particle is released there from rest and arrives at location B with a speed vB. The potential at location C is 1060 V, and when released from rest from this spot, the particle arrives at B with twice the speed it previously had, or 2 vB. Find the potential at B.
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A +3.0 charge is at and a -1.0 charge is at .
At what point or points on the x-axis is theelectricpotential zero?
X = ___________ cm
A -2.0 charge and a +2.0 charge are located on the x-axis at and , respectively.
At what position or positions on the x-axis is theelectricfield zero?
At what position or pos

Please help with the following problems.
1. In the figure, two charges q1=+3.0uC and q2=-2.0uC are separated by 6.0cm.
a. Find theelectric forces exerted on each other (magnitudeand direction)
b. Find theelectricfield from point P, which id 4.0cm to the right q2 (megnitude and direction).
c. Find the positions along t

ElectricField
Four identical point charges (q = + 10.0 micro coulomb) are located on the corners of a rectangle. The dimensions of the rectangle are L = 60.0 cm and W = 15.0 cm. Calculate themagnitudeand direction of the resultant electric force exerted on the charge at the lower left corner by the other three charges.

Hi. Can someone please explain to me what exactly theelectricpotential is and how it differs from electricpotential energy -- not with equations, but in prose. (Or at least, with both.) I can read the equation, but I don't really understand what electricpotential IS. What is its significance?
Thank you!

Problem 1
A charge is moved from one place to another in an electricfield. In which of the following situations will the change in potential energy be NON-ZERO?
the charge is only moved perpendicular to all electricfield lines that it crosses
the charge remains unmoved
the charge is moved along an equipotential surfa

Point charges q1=- 5.00 nC and q2=+ 5.00 nC are separated by distance 3.80 mm, forming an electric dipole.
A) Find themagnitude of theelectric dipole moment in Cm.
B) The charges are in a uniform electricfield whose direction makes an angle 36.5 degrees with the line connecting the charges. What is themagnitude of this

Does theelectricfield always move from positive to negative?
If I'm told that a uniform electricfield of magnitude 4.1 x 10^5 N/C points in the positive x direction, and a 4.5 micro-C charge moves 6.0 m in the positive x direction, and to find theelectricpotential energy (which is -11 J), does my equation look like this:

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 thepotential on the outer surface of the membrane is +70.0 mV greater than that on the inside s

Four quick conceptual questions:
1) Is theelectricfield (E = -delta V / delta s) always a positive number (or zero)? That is, is it always the absolute value of themagnitude of theelectricfield? Or can it have a negative value?
2) Is electricpotential (delta V) always negative? The answer to one of the questions in m