Friction is reduced in a moving maglev train by lifting it above its track by magnetic repulsion. What are the advantages of reducing friction between the train and the track ?

The electric potential v is constant everywhere within a certain region of space. which statement below is true? the choices are: the electric field is also constant (but not zero) within the region. a charged particle placed within the region will experience an electric force. the electric field is zero everywhere within the region. the electric field varies from place to place within the region.