Question

A 4.85 μF capacitor is initially charged to a potential of 16.4 V . It is then connected in series with a 3.50 mH inductor.

1.What is the total energy stored in this circuit?

Express your answer in joules to three significant figures.

2.What is the maximum current in the inductor?

Express your answer in amperes to three significant figures.

3.What is the maximum current in the inductor?

Express your answer in amperes to three significant figures.

Answer 1

Capacitance of the capacitor, C = 4.85 F = 4.85 x 10^-6 F

Potential across the capacitor plates, V = 16.4 V

Inductance of the capacitor, L = 3.50 mH = 3.50 x 10^-3 H

(1) Total energy stored in the circuit = Initial Energy stored in the capacitor

= (1/2)*C*V^2

= 0.5*(4.85 x 10^-6)*16.4^2

= 6.52 x 10^-4 J

(2) Suppose the maximum current in the inductor = Im

The current in the inductor will be maximum when all the energy of the capacitor will transfer in the inductor.

Means,

(1/2)*C*V^2 = (1/2)*L*Im^2

=> (1/2)*L*Im^2 = 6.52 x 10^-4

=> Im^2 = (2 x 6.52 x 10^-4) / (3.50 x 10^-3)

=> Im = 0.610 A (Answer)

(3) Same question as asked in (2). So, answer will be the same.

Im = 0.610 A (Answer)