15 Application of Faraday’s Law – Motional emf What is motional emf?How is it produced?The force on chargesThe potential difference
16 Motional emf in a Circuit How do I calculate motional emf?Motional emf and BatteryWhat is the resulting current?
17 ExampleAs shown, a metal rod makes contact with a partial circuit and completes the circuit. The circuit area is perpendicular to the magnetic field with B=0.15T. If the resistance of the total circuit is 3 ohm, how large a force is needed to move the rod as indicated with a speed of 2 m/s.
18 Lenz’ Law Revisited – Moving Bar Example How do I calculate the direction of induced current?One possibility
19 Lenz’ Law, Bar ExampleAnother possibilityConservation of energy
20 Lenz’ Law – Moving Magnet Example When applying Lenz’ Law, there are two magnetic fields to considerThe external changing magnetic field that induces the current in the loopThe magnetic field produced by the current in the loop
21 AC GeneratorsWhat is a generator?How does it work?Emf of the loop
24 Joseph Henry 1797 – 1878 First director of the Smithsonian First president of the Academy of Natural ScienceFirst to produce an electric current with a magnetic fieldImproved the design of the electro-magnetic and constructed a motorDiscovered self-inductance
25 Self-inductance What is self-inductance? How do I calculate it? What are it SI units?What is inductance?
26 ExampleA coiled telephone cord has 70 turns, a cross-sectional diameter of 1.3 cm, and an unstrectched length of 60 cm. Determine an approximate value for the self-inductance of the unstretched cord.
27 Inductor and RL Circuit What is an inductor?How does it work in a circuit?RL circuitWhat is the time constant?How do I find the current in the circuit?What is the energy stored in the inductor?
28 Example For the circuit shown, determine Time constant Current after one time constantChange in potential at t=0 and t=first time constantThe rate of change of current after first time constant