Calculate the electric field strength inside and outside a wire

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Homework Help Overview

The problem involves calculating the electric field strength inside and outside an infinitely long conducting cylinder with a uniform surface charge density. The context is rooted in electrostatics and the application of Gauss's law.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the application of Gauss's law, questioning how to determine the charge enclosed by a Gaussian surface. There are attempts to integrate and substitute values into the equations provided, with some uncertainty about the correct approach.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the use of Gaussian surfaces and the implications of the conductor's properties, but no consensus has been reached on the specific calculations.

Contextual Notes

Participants are navigating assumptions about the charge distribution and the geometry of the Gaussian surfaces, with some uncertainty about the correct application of formulas and the area calculations involved.

matt_crouch
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Homework Statement



An infinitly long conducting cylinder of Radius R carries a inform surface charge of (lambda per unit length) determine the electric field strength inside and outside the cylinder

Homework Equations



integral (E.ds)= q/e0

The Attempt at a Solution



im not really sure what to do at all i tried simply differentiating the equation above and substituting lambda in for q but I am pretty sure that's not right...
 
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First, the field inside is easiest to start with. The q in integral (E.ds) = q/e0, is the charge inside a gaussian surface. So a gaussian surface inside the conductor encloses how much charge? ... so the electric field is...?

Next, you need to simply integrate the left side of the equation after subtituting dr for ds. Then use a gaussian surface of some length l, and figure out what the q enclosed is and plug that into the right side.
 
so since its a Gaussian surface do i calculate the line charge density by integrating lambda from R to infinity? then substitute that into the equation above?
 
Electric field inside the cylinder is zero. Because that is conductor material
 
ok so outside the conductor do i just use the E=q/4(pi)e0R^2 ?
 
matt_crouch said:
so outside the conductor do i just use the E=q/4(pi)e0R^2 ?
It's not correct. What is area of Gaussian surface?
 
ahhh so i need to use the area of a cylinder? so 2(pi)rh +2(pi)r^2 ?
 

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