# Magnetic Field's Equation's querry.

1. Oct 18, 2008

### kloong

1. The problem statement, all variables and given/known data
B = (miu0)I / 2(pie)(rho) X an

how do i know the direction of the an? if it is ax, ay or az?

2. Relevant equations

2. Oct 18, 2008

### Staff: Mentor

The field from a long straight current-carrying wire is given by:

$$B = \frac{\mu_0 I}{2 \pi r}$$

Does your question relate to this?

3. Oct 18, 2008

### kloong

yes indeed. and besides that equation, there's suppose to be a unit vector, right? i was wondering how do i know the direction of the unit vector.

4. Oct 18, 2008

### Staff: Mentor

The direction of the field--and the unit vector--is given by the right hand rule. See: "http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html#c1" [Broken]

Last edited by a moderator: Apr 23, 2017 at 4:34 PM
5. Oct 18, 2008

### kloong

awesome! thanks alot.

at least something good happened today. haih. i just got robbed.