- Physics Question [SOLVED]
- 26 Feb 2015 10:28:25 pm
- Last edited by MateoConLechuga on 27 Feb 2015 04:08:38 pm; edited 1 time in total

Okay, I've been thinking about this problem for a little bit, and I think I've got it worked out, but I am a little unsure of how to work out the final part. So, here goes:

Question: So, here's the question:

a) Using Gauss's Law, derive an expression for the total electric field in the space between the two wires.

b) What is the potential difference between the two wires?

c) Show that the capacitance per unit length of this pair of wires is: C/(length of wire)= (πε₀)/(ln((D-r)/r)

So far, here is my interpretation:

a) I determined that the electric field of one wire is E=λ/(2πε₀*R), which I then figured that the total field is E=σ/(ε₀)...

b) To get the potential difference, I did the following:

V=∫Eds (Integrated from a to b)

V=E∫ds

V=Ed

c) For c, I am not really sure where to begin...

I could probably spent some more time on it and work it out fully; I just wanted to see how far off I am, and how I could go about thinking about it. Any input and ideas are much appreciated! Thank you so much in advance!

**Code:**```
Consider two long, parallel and oppositely charged wires of radius 'r' with their centers separated by a distance D (D>>r). The charges are uniformly distributed strictly on the surface of each wire, with a line charge density λ.
```

------------------------------- (-) -Wire a

↑

D

↓

------------------------------- (+) --Wire b

Question: So, here's the question:

a) Using Gauss's Law, derive an expression for the total electric field in the space between the two wires.

b) What is the potential difference between the two wires?

c) Show that the capacitance per unit length of this pair of wires is: C/(length of wire)= (πε₀)/(ln((D-r)/r)

So far, here is my interpretation:

a) I determined that the electric field of one wire is E=λ/(2πε₀*R), which I then figured that the total field is E=σ/(ε₀)...

b) To get the potential difference, I did the following:

V=∫Eds (Integrated from a to b)

V=E∫ds

V=Ed

c) For c, I am not really sure where to begin...

I could probably spent some more time on it and work it out fully; I just wanted to see how far off I am, and how I could go about thinking about it. Any input and ideas are much appreciated! Thank you so much in advance!