Question

a satellite orbitting the earth at the equator at a na ltitude of 400 km, has an antenna that can be modelled as a 2.0m long rod. the antenna is oriented perpndicular to the earth's surface. at the equator, the earth's magnetic field is essentially horizontal and has a value of 8.0*10^-5 t;ignore any change in B with altitude. assuming the orbit is circular, determine the induced emf between the tips of the antenna.

Answer 1

Compute the orbital speed V at that altitude, in m/s. It should be several thousand m/s. You can get it by equating the centripetal force to the gravity force. You will need the earth's radius.

Charge q in the rod experiences a force B*V*q. Along length L, there will be a voltage difference B*V*L.
B is the mag. field in Tesla and L is the antenna length in meters.