Science Group
Question:
The electromotive voltage of a generator is E=10V and it's internal resistance is r=10 Ohms.
The generator is connected with a coil with inductance L=0.10H and negligible internal resistance, which has in parallel link a capacitor with C=0.10 miuF.At one time, the switcher is opened.Find the maxim voltage at coil polarities.
Answers:
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eNotes Editor
Posted by giorgiana1976 on Tuesday July 21, 2009 at 10:55 AMBest answer as selected by question asker.
In DC without oscillations, with closed switch, an ideal coil is a short circuit, and an ideal capacitor is a pause circuit. In these conditions, the power will be just in coil and the energy of oscillating circuit is the magnetic energy of the coil I=E/r and W=Wm=LI^2/2 After switch opening the oscillating circuit remains disconnected from the battery, having the initial energy W=Wm and in circuit appear oscillations. When the voltage is maximum, the power is void and from energy preservation , we have: (1/2)CUm^2=(1/2)LI^2 Um=I*sqrt (L/C)=1 kV

