Magnetic field in the center of the toroid

[JasonBourneV]

Can't this be calculated from B = mu*N*I/2*pi*r? Book explanation says that this can't be done because there is "no path through the center along which the field is constant" So I guess I must use the Biot-Savart Law. How should I go about doing that?

[Doc Al]

Magnetic Field of Current Loop (http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/curloo.html#c1)

[JasonBourneV]

Thanks a lot, Doc Al, for the link!