1. Today4/28  Lab: Electromagnetic Induction Last one!  Final Exam Topics  waves  interference  refraction  lenses/mirrors  E-Fields  potential  plates  capacitance  circuits  B-fields

2. Final Exam  Tuesday, 5/13, 10:15am Witmer 116  Problems pulled from  Lecture  HW  exams  We will cover a small amount of new material as we review. New material will be details of old material.

3. Motional EMF v B Pos. charges cannot move, Neg. charges shift down. Rod has net pos at top and net neg at bottom. Rod becomes a battery with a  V = EMF

4. Motional EMF v B If in a circuit, current will flow. V = IR etc. Careful, only the rod can move. Why? Right-hand wire would also have an EMF (opposing).

5. Motional EMF v B How big is EMF? Depends on: Velocity EMF = vBL when v, L, and B all 90°. B-field Length of rod Units of Volts (or J/Coul)

6. Motional EMF v B Problem solving. Energy conservation! Newton’s laws! Work done on bar = energy dissipated in the resistor Force on the bar is balanced if at constant speed (Force of the external agent = mag. Force, IlB.

7. Motional EMF v B What is the force on the bar by the rope if it is pulled at constant a speed of 2m/s through a 3T field? The bar is 0.5m long and the resistor is 5 . Frictionless conducting rails