Calculating Magnetic Field Due to a Current at a Given Point

[GeorgeCostanz]

Homework Statement

A current of 4.60 A is located at the origin, flowing along the z axis. (A positive current flows in the + k direction.) Find the magnetic field at the point (2.79,3.89) cm.

Enter the x and y components of the field:

Homework Equations

B = μ$_{°}(i)$/(2∏r)

μ$_{°}$ = 4∏ x 10^-7

The Attempt at a Solution

used the Pythagorean theorem to find r = 0.04787

used ampere's law to find B = 1.92x10^-5 T

found θ at 54.35°

from there i found

Bx = Bcosθ = 1.12x10^-5 T
By = Bsinθ = 1.56x10^-5 T

not sure where I'm going wrong, thanks

 

[kushan]

How did you find angle?

 

[GeorgeCostanz]

arctan(3.89/2.79)

 

[kushan]

George , what will be the direction of magnetic field at that point,?

 

[GeorgeCostanz]

i'm not sure, I'm struggling with all this right hand rule stuff

 

[kushan]

See , you need to know is ,
The magnetic field will form concentric circles around the wire ,
and the direction of magnetic field at any point will be the tangent of the circle at that point .

 

[kushan]

This is the figure