An LC circuit consists of a capacitor with C = 2.9 μF and an inductor with L = 30 mH. At t = 0 the capacitor has charge 6.3 μC and the current in the inductor is zero. The circuit oscillates at its resonant frequency. How long after t = 0 will the current in the circuit be maximum?
What will be this maximum current?

Respuesta :

Answer:

Explanation:

In the L-C oscillation , energy is transferred between capacitor and inductor with a certain periodicity.

Initial energy in the capacitor = 1/2X Q² / C

[tex]\frac{(6.3\times10^{-6})^2}{2\times2.9\times10^{-6}}[/tex]

= 6.84 x 10⁻⁶ J

Initial energy of inductor is zero.

Total energy = 6.84 x 10⁻⁶ J

When all the energy is stored in the inductor , it has maximum current . Let this current be I

Energy of inductor

= 1/2 L I²

Here I is maximum current in the inductor.

Conserving energy

1\2 L I² = 6.84 X 10⁻⁶

.5 X 30 X 10⁻³ I² = 6.84 X 10⁻⁶

I = 2.13 X 10⁻²

= 21.3 mA.

Time period of oscillation

T = [tex]2\pi\sqrt{LC}[/tex]

=[tex]2 X 3.14 \sqrt{30\times10^{-3}\times2.9\times10^{-6}}[[/tex]

188.4 10^{-5}.s

Current will be maximum after 1/ 4 of time period

= .25 x 188.1 x 10⁻⁵ s

47 X  10⁻⁵ s

Answer:

0.02654618617 seconds

Explanation:

[tex]I=I_{max} sin(ωt-Φ)[/tex]

In this case you want to find the maximum current. So [tex]I=I_{max}[/tex]

[tex]I/I_{max}=sin(ωt-Φ)[/tex]          phi is 0

your resonance is going to be the capacitance and the inductance and then solve for t.[tex]sin^{-1}(1)=ωt[/tex]