PHY 2049: Physics II Tutoring Center is open in room NPB 1215, M-F 12:00AM -4:00PM. It is free.

Ch. 30 Induction and Inductance Magnetic Flux Faraday’s Law of Induction Lenz’ law Inductors Self and Mutual Series RL circuits Magnetic Energy

     PHY 2049: Physics II

PHY 2049: Physics II When the switch is first thrown      PHY 2049: Physics II When the switch is first thrown The inductors block any current. All current flows through the middle resistance. I = V/R Later, the inductors are all closed and the current is then I = 3V/R. How much time does it take for the current to rise?

On R-L circuits When the switch S in the circuit shown is closed, the time constant for the growth of current in R2 is: V = L dI/dt +IR2

4 1 2 3 hitt The four wire loops shown have edge lengths of either L, 2L, or 3L. They will move with the same speed into a region of uniform magnetic field B, directed out of the page. Rank them according to the maximum magnitude of the induced emf, least to greatest. A. 1 and 2 tie, then 3 and 4 tie B. 3 and 4 tie, then 1 and 2 tie C. 4, 2, 3, 1 D. 1, then 2 and 3 tie, then 4 E. 1, 2, 3, 4

Electromagnetic Osciallations and Alternating Current Current changes expo in an R-L circuit Charge changes expo in an R-C circuit Sinusoidal in and L-C circuit Analogous to a harmonic Oscilaltor

The Potentials Charge up a capacitor, plug in an inductor and unplug battery. Pot across inductor oscillates. The potential across a capacitor oscillates.

Alternating Currents A resistance

Alternating Currents The current leads the voltage

Inductor The current lags the voltage