Wire in Field


by Soaring Crane
Tags: field, wire
Soaring Crane
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#1
Feb11-05, 07:10 PM
P: 483
A very long straight wire has charge per unit length 1.4910-10 C/m.


At what distance from the wire is the magnitude of the electric field equal to 2.49 N/C?



Use 8.8510-12 C^2/(N*m^2) for the permittivity of free space and use pi = 3.1416 for E = (lambda)/(2*pi*permittivity of free space*r).

Given:
E = 2.49 N/C

I have no idea what to do with this formula. Why is wavelength needed and what is the variable we are trying to find? I am lost.

Thanks.
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Doc Al
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#2
Feb11-05, 07:16 PM
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Quote Quote by Soaring Crane
Why is wavelength needed and what is the variable we are trying to find? I am lost.
In this formula, lambda stands for the "charge per unit length", not wavelength. You are trying to find the distance from the wire, which is "r".
dextercioby
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#3
Feb11-05, 07:22 PM
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[itex] \lambda [/itex] is not a wavelength,it's the linear charge density and it's measured in C/m.
Plug in all the numbers in the formula & see what happens...

Daniel.


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