1. PHY 2049: Physics II Tutoring Center is open in room NPB 1215, M-F 12:00AM -4:00PM. It is free. The following hitt numbers need to register. Please do so ASAP. 402407405767416479 402614406876417029 432808411209420713 432798

2. Ch. 31 Electromagnetic Oscillations RC, RL, LC circuits Driven damped Oscillations Resonance Series RLC circuits Power Transformer

3. Last time LC circuit Analogous to a pendulum Lm qx C1/k Be careful with ωt in radians (not degrees)

4. Alternating Currents A resistance The current and voltage are in phase

5. Capacitor: AC response The current leads the voltage

6. Inductor: AC response The current lags the voltage

7. HITT A capacitor in an LC oscillator has a maximum potential difference of 15V and a maximum energy of 360 μJ. At a certain instant the energy in the capacitor is 40 μJ. At that instant what is the potential difference across the capacitor? A. zeroB. 5VC. 10VD. 15V E. 20V

8. An LC circuit has a capacitance of 30 μF and an inductance of 15mH. At time t = 0 the charge on the capacitor is 10 μC and the current is 20mA. The maximum charge on the capacitor is: A. 8.9 μC B. 10 μC C. 12 μC D. 17 μC E. 24 μC A different problem

9. Yet different A 45-mH inductor is connected to a source of sinusoidal emf with a frequency of 400 Hz and a maximum emf of 20V. The maximum current is: A. 0 B. 0.18A C. 1.1A D. 360A E. 2300A ans: B

10. RLC circuit

11. RLC circuit Inductive Capacitive In resonance

12. e = E sin ωt i = i o sin (ωt –φ) Capacitor current leads Power = I 2 R = e rms i rms cosφ (cos φ =R/Z)

14. Resonance

15. Transformers