Motion  Current: Generating Electricity (Faraday’s law) 1. A current appears only if there is relative motion. Fast motion produces a greater current. 3. Clockwise/counter clockwise current with north pole move in/out. Opposite with south pole. Induced current in secondary coil, if there is change of current in the primary coil: switch or ac current Transformer

Faraday’s Law of Induction Magnetic flux through area A Amount of magnetic field passes through an area A For uniform B: (Weber, or Wb, or T m2 Faraday’s Law of Induction: An emf is induced in a loop when the magnetic flux that pass through the loop is changing. The the loop is conducting, then a current will flow. For a loop with N turns: Change B (change current) Change A Change angle between them

Current loop in magnetic field: Motors •  B B F L  •  w

Torque on a Current Loop: Motors F F  B •  F B •  B •  n  n n F

Torque on a Current Loop: Continuous B •  F n B •  F  n B •  F n B •  F B •  F