You are performing studies of the possibility of migrating birds using the earth's magnetic field for navigation. to modify the magnetic field in the brain of a bird, you fit the bird with coils as "caps" and "collars"

the data on the coils indicate that they each have 210 q of resistance, a radius of 1.20 cm, and 50 turns of wire. the centers of the coils are separated by 2.05 cm. you wish to create an "earth-like" magnetic field of 4.0 x 105 t at the midpoint of the axis between the coils. given this data, you need to determine the voltage of the battery (in v) needed to power the coils

v=