In studies of the possibility of migrating birds using the Earth's magnetic field for navigation, birds have been fitted with coils as "caps" and "collars" as shown in the figure below.
(a) If the identical coils have radii of 1.21 cm and are 2.32 cm apart, with 30 turns of wire apiece, what current should they both carry to produce a magnetic field of 4.00 multiply.gif 10-5 T halfway between them?
(b) If the resistance of each coil is 215 ?, what voltage should the battery supplying each coil have?
(c) What power is delivered to each coil?