Lecture%2026%202220%20Spring%202009

# Lecture%2026%202220%20Spring%202009 - Reminders and...

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1 Reminders and Announcements Exam 2 is this afternoon at 4:15 p.m. Chs. 27-30 HW 16 is due Friday. Help Room Hours (Physics 117): M 4-8 pm, T 3-6:30, W 3-6:30, R 4:30-8, F 2-6 Self-Inductance A self-induced emf is always proportional to the time rate of change of the current For a coil of N turns carrying current I: I L d εL dt II BL N ε L d dt RL Circuit, Analysis An RL circuit contains an inductor and a resistor When the switch is closed (at time t = 0), the current begins to increase At the same time, a back emf is induced in the inductor that opposes the original increasing current 0 I I d ε R L dt 1 I Rt L ε e R What is the effect of increasing the resistance in the preceding circuit? 0 of 5 1 2 3 4 25% 25% 25% 25% 1. Decreases time constant 2. Decreases maximum current 3. Increases time constant 4. Both 1 and 2 Energy in a Magnetic Field Part of the energy supplied by the battery appears as internal energy in the resistor The remaining energy is stored in the

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Lecture%2026%202220%20Spring%202009 - Reminders and...

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