821.1 Faraday's law of electromagnetic induction energy conversion Outside the circuit: ←田 F4F←田 ←田→ F Fd/>0 Inside the circuits F d/<0 K R ∮F:d=0 How about F? F Define the nonstatic electric field Ek A=SE. di>o Not a conservative force 821.1 Faraday's law of electromagnetic induction Define the emf emf=F Ed emf is the measure of the capacity of transforming the emf= Edi other form energy to electric energy. (inside) Direction of the emf3 energy conversion： ⋅d = 0 ∫ F l L e r r Fe← ⊕ r ← ⊕ Fe r + − K R ←⊕→ Fk r Fe r ∫ + − Fe ⋅dl < 0 r r ∫ − + Fe ⋅dl > 0 r r Fe r Outside the circuit： Inside the circuit： Fk r How about ? 0 q F E k k r r Define the nonstatic electric field = = ⋅d > 0 ∫ A E l L k r r Not a conservative force §21.1 Faraday’s law of electromagnetic induction E l L k r r emf= ⋅d ∫ Define the emf ∫ + − = ⋅ （inside） emf E dl k r r emf is the measure of the capacity of transforming the other form energy to electric energy. + − Direction of the emf §21.1 Faraday’s law of electromagnetic induction