Calculate Magnetic Field from Current on a Loop of Wire

[fball558]

magnetic field ??

Homework Statement

A single loop of wire of radius 3 cm carries a current of 2.4 A. What is the magnitude of B on the axis of the loop at the following position?
1 cm from the center

Homework Equations

Uo/4(pi) * (2(pi)R^2 *I) / (z^2 + R^2)^(3/2)

where Uo is 4(pi) X 10^-7

The Attempt at a Solution

i just pluged in values
R = .03 m
z = .01 m
I = 2.4 A

i got 4.2357797e-4 T but that is wrong??
does anyone see something that I am doing wrong?
any help would be great!

 

[jchojnac]

for x = 0 (at center of loop)

B = (μ0)*(I)/(2*R)

don't know how to get b, c, or d yet though.