Hi,(adsbygoogle = window.adsbygoogle || []).push({});

I'm having trouble visualizing the way to calculate magnetic flux inside a wire and I was hoping someone here could help me.

[tex]\Phi_B = \oint B \cdot dA[/tex]

Inside a wire, using ampere's law, I got:

[tex] B = \frac{\mu_0 i}{2\pi}\frac{r}{R^2} [/tex]

And that's where I get stuck. http://img23.photobucket.com/albums/v68/AngelOfMusic/wire.jpg" [Broken] of the wire, it seems that B is perpendicular to dA everywhere.

In the book's solution, they had this perspective of the wire:

http://img23.photobucket.com/albums/v68/AngelOfMusic/wire2.jpg" [Broken] And it suddenly makes sense.

I was just wondering if someone could point out to me how the two diagrams relate? I'm having trouble going from one perspective to the next.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Visualization of a wire & magnetic field

**Physics Forums | Science Articles, Homework Help, Discussion**