MasteringPhysics Assignment Print View

MasteringPhysics Assignment Print View - HW 07 Due 11:00pm...

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HW 07 Due: 11:00pm on Friday, April 8, 2011 Note: To understand how points are awarded, read your instructor's Grading Policy . [Switch to Standard Assignment View ] Current Through LR Circuits Ranking Task The figures below show six circuits which consist of identical ideal batteries, resistors, and inductors. All of the switches are closed at the same time. Part A Rank the circuits based on the current through the battery immediately after the switch is closed. Hint A.1 Ideal inductors in circuits Hint not displayed Hint A.2 Replacing inductors with "opens" Hint not displayed Hint A.3 Replacement in a circuit Hint not displayed Hint A.4 Replacement in a circuit Hint not displayed Rank from largest to smallest. To rank items as equivalent, overlap them. ANSWER: View Correct Part B Rank the circuits based on the current through the battery a very long time after the switch is closed. Hint B.1 Replacing inductors with "shorts"

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Hint not displayed Hint B.2 Replacement in a circuit Hint not displayed Hint B.3 Replacement in a circuit Hint not displayed Rank from largest to smallest. To rank items as equivalent, overlap them. ANSWER: View Correct Oscillations in an LC circuit. Learning Goal: To understand the processes in a series circuit containing only an inductor and a capacitor. Consider the circuit shown in the figure. This circuit contains a capacitor of capacitance and an inductor of inductance . The resistance of all wires is considered negligible. Initially, the switch is open, and the capacitor has a charge . The switch is then closed, and the changes in the system are observed. It turns out that the equation describing the subsequent changes in charge, current, and voltage is very similar to that of simple harmonic motion, studied in mechanics. To obtain this equation, we
will use the law of conservation of energy. Initially, the entire energy of the system is stored in the capacitor. When the circuit is closed, the capacitor begins to discharge through the inductor. As the charge of the capacitor decreases, so does its energy. On the other hand, as the current through the inductor increases, so does the energy stored in the inductor. Assuming no heat loss and no emission of electromagnetic waves, energy is conserved, and at any point in time, the sum of the energy stored in the capacitor and the energy stored in the inductor is a constant : , where is the charge on the capacitor and is the current through the inductor ( and are functions of time, of course). For this problem, take clockwise current to be positive. Part A Using the expression for the total energy of this system, it is possible to show that after the switch is closed, , where is a constant. Find the value of the constant . Hint A.1

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This note was uploaded on 04/25/2011 for the course PHYSICS 2760 taught by Professor Pualmiceli during the Spring '10 term at Missouri (Mizzou).

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MasteringPhysics Assignment Print View - HW 07 Due 11:00pm...

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