Calculating Magnetic Field with Helmholtz Coils

[sheri1987]

Homework Statement

The coils in a set of Helmholtz coils have 186 turns and a radius of 15.9 cm. The current is set at 2.2 A. Express your answers in units of "T" for Tesla.

a) Calculate the magnetic field along the axis at the center of the two coils (x = 0).

b) What is the magnetic field at the center if the currents in the two coils are going in opposite directions?

Homework Equations

B= (KN/R) *I <-----used for part A

The Attempt at a Solution

I obtained the correct answer of .0023 Tesla for part a); however, I am unsure how to do part b) ...any help?

 

[phyzmatix]

If the current flows in opposite directions, the induced magnetic fields will be directed away from each other wouldn't they? I'm no expert at coils, but I'd look at the possibility of treating the two halves separately...