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

In summary, the voltage across a membrane forming a cell wall is 78.7 mV and the membrane is 8.52 nm thick. Using the equation E=-Vd, the electric field strength is calculated to be 9237089 V/m. It is important to note that the negative sign in the equation may be included or not, depending on the context.
  • #1
elowe93
4
0

Homework Statement



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.

Homework Equations



E=-Vd

The Attempt at a Solution



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

i don't understand why this is wrong?
 
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  • #2
elowe93 said:

The Attempt at a Solution



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

i don't understand why this is wrong?

The problem stated that the voltage was 78.7 mV, but you have written that down as 0.00787=7.87mV. Also check your multiplication.
 
  • #3
You should not have multiplied.
 
  • #4
use unit analysis. What are the units of an e field? what are the units of voltage?
 
  • #5
Okay, so i did E=(.0787)/(8.52e-9) to get 9237089 V/m is this correct? or should it be negative because in some of the equations I am finding for this it has a negative. I feel like it should be positive though is this right?
 

FAQ: Help finding the electric feild strength in a uniform E-field

What is a uniform electric field?

A uniform electric field is a type of electric field in which the magnitude and direction remain constant throughout the region. This means that the electric field lines are evenly spaced and parallel to each other.

How is electric field strength measured?

Electric field strength is measured in units of volts per meter (V/m). It can be calculated by dividing the force experienced by a charged particle in the electric field by the charge of the particle.

What factors affect the strength of a uniform electric field?

The strength of a uniform electric field is affected by the magnitude and direction of the charges creating the field, as well as the distance from the charges and the medium in which the field exists.

How do you find the electric field strength in a uniform electric field?

The electric field strength in a uniform electric field can be found by dividing the voltage between two points in the field by the distance between those points. It can also be calculated by dividing the force on a test charge by the magnitude of the charge.

What are some real-world applications of uniform electric fields?

Uniform electric fields are used in various technologies, such as particle accelerators, cathode ray tubes, and capacitors. They are also important in understanding the behavior of charged particles in space, such as in Earth's ionosphere.

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