uploaded image  Image text transcribed for accessibility: Two
thin circular coxial coils each of radius a, having N turns,
carrying current I, and seperated by a distance d, are lettered
to as Helmholtz coils for the case when d=a. This set up is well
known for producing an approximately uniform magnetic field in
the vicinity of its center of symmetry. Find B on the axis of
symmetry-the z axis- of the Helmholtz coils. show that dBz/dz=0
at the point p midway between the two coils.  Want an answer?