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Find the charge q(t) on the capacitor and the current i(t) in the given LRC-series circuit. L = 5/6 h, R = 10 Ω, C = 1/60 f, E(t) = 300 V, q(0) = 0 C, i(0) = 0 A

User Motatoes
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The charge on the capacitor (q(t)) is represented by 30t, and the current (i(t)) is given by -(6/5) * 30e^(-5t/6) + 30, calculated through LRC circuit analysis.

Certainly! Let's go through the detailed calculations to find the charge q(t) on the capacitor and the current i(t) in the given LRC-series circuit.

The differential equation governing the circuit is:

L * (di/dt) + Ri + (1/C) * q = E(t)

Given values:

L = 5/6 H, R = 10 Ω, C = 1/60 F, E(t) = 300 V, q(0) = 0 C, i(0) = 0 A

First, we can express the differential equation in terms of q(t):

(5/6) * (di/dt) + 10i + (60/1) * q = 300

Now, let's find the homogeneous solution to this differential equation:

L * (di_h/dt) + Ri_h + (1/C) * q_h = 0

(5/6) * (di_h/dt) + 10i_h + 60 * q_h = 0

The homogeneous solution is found by assuming i_h(t) = Ae^(rt) and q_h(t) = Be^(rt), where A and B are constants.

Substituting these into the homogeneous equation and solving, we get:

i_h(t) = -(6/5) * Ae^(-5t/6)

q_h(t) = (1/5) * Be^(-5t/6)

Now, let's find the particular solution to the complete differential equation. We assume i_p(t) = A (a constant) to simplify calculations.

Substituting this into the differential equation, we get:

(5/6) * (di_p/dt) + 10i_p + 60 * q_p = 300

(5/6) * (0) + 10A + (60/1) * q_p = 300

Solving for A, we find A = 30.

Now, we have the complete solution:

i(t) = i_h(t) + i_p(t) = -(6/5) * 30e^(-5t/6) + 30

q(t) = q_h(t) + q_p(t) = (1/5) * 0e^(-5t/6) + 30t

Now, apply the initial conditions to find B:

q(0) = 0 = (1/5) * B + 0

B = 0

The final expressions are:

i(t) = -(6/5) * 30e^(-5t/6) + 30

q(t) = 30t

User Rgullhaug
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