821.1 Faraday's law of electromagnetic induction @2Induced current and induced electric field A current exists in the wire loop with the galvanometer as long as the magnetic flux through the loop is changing with time. Such current is called induced current What makes the charge move and causes the current? F=ge Maxwell: induced electric field-changing magnetic field flux through a loop induces an electric field, that causes the charge to move and produce the electric current. s 21.1 Faraday's law of electromagnetic induction Maxwell: new effect d④ induced emf= B·d4 d④ induced emf= ∫ dA dt dt emfE·dcmf=「E4d (inside) 88 ②Induced current and induced electric field A current exists in the wire loop with the galvanometer as long as the magnetic flux through the loop is changing with time. Such current is called induced current. Maxwell: induced electric field—changing magnetic field flux through a loop induces an electric field, that causes the charge to move and produce the electric current. What makes the charge move and causes the current? F qE r r = §21.1 Faraday’s law of electromagnetic induction t Φm d d induced emf = − ∫ Φm = B⋅ A r r d A t B t Φm r r d d d d d induced emf = − = − ⋅ ∫ E l L k r r emf= ⋅d ∫ ∫ + − = ⋅ （inside） emf E dl k r r §21.1 Faraday’s law of electromagnetic induction Maxwell: new effect