A satellite in a low Earth orbit deploys a conducting tether of length 12 km that extends radially outwards from the Earth. The satellite and tether travel horizontally at an orbital speed of 7.5 km s-1 through a region where the Earth's magnetic field is perpendicular to both the tether and its direction of motion.
If the magnetic flux density in this region is 4.5×10−5 T4.5 \times 10^{-5}\text{ T}4.5×10−5 T, what is the magnitude of the electromotive force (emf) induced across the ends of the tether?
4.05 mV4.05\text{ mV}4.05 mV
4.05 V4.05\text{ V}4.05 V
4.05 kV4.05\text{ kV}4.05 kV
4.05 MV4.05\text{ MV}4.05 MV