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.
![1251_Migrating birds.gif](https://secure.tutorsglobe.com/CMSImages/1251_Migrating%20birds.gif)
(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?