# 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...

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.

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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**