Practice question

**Rectangular loop moving out of field** emf e = B l v, l side perpendicular to motion cutting field lines, e constant while partially in field, zero when fully out, duration t = (side parallel to motion)/v. For 0.38×0.55 m loop B=0.65 T v=0.7 m/s along shorter side 0.38 m, l=0.55 m (side cutting), e=0.65×0.55×0.7=0.25 V, lasts t=0.38/0.7=0.54 s. Motional emf requires the rod to move perpendicular to the magnetic field to cut flux lines. Moving parallel to its length does not change the flux through any area, so no emf is induced. Using Φ = B A cosθ, e = -N dΦ/dt = -N