How Do You Calculate the Magnetic Field at a Point Near a Current-Carrying Wire?

[cmcrus02]

Homework Statement

4. A long straight wire lies along the z-axis and carries an 8 A current in the +z direction. Find the magnetic field (magnitude and direction) produced at x=0.4 m, y=0, z=0.3 m by a 0.7 mm segment of wire centered at the origin.

Homework Equations

dB=(mu/4pi)(I[dL x r])/r^2
dB, dL, and first r are vectors

The Attempt at a Solution

 

[cupid.callin]

Show us your attempt

 

[cmcrus02]

The test is in 2 hours, I've attempted it and feel the answer is right, but am not going to show all that work during this crunch time, be a sport, I think the problem is setting up the vectors correctly and doing the cross product correctly,

 

[berkeman]

Homework Statement

4. A long straight wire lies along the z-axis and carries an 8 A current in the +z direction. Find the magnetic field (magnitude and direction) produced at x=0.4 m, y=0, z=0.3 m by a 0.7 mm segment of wire centered at the origin.

Homework Equations

dB=(mu/4pi)(I[dL x r])/r^2
dB, dL, and first r are vectors

The Attempt at a Solution

The test is in 2 hours, I've attempted it and feel the answer is right, but am not going to show all that work during this crunch time, be a sport, I think the problem is setting up the vectors correctly and doing the cross product correctly,

You must show us your work and attempt at a solution before we can offer tutorial help. Them's the rules here.