(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

For the circuit shown below, the capacitors are initially uncharged. At t=0, the switch S is closed.

a) Determine the current in each resistor immediately after the switch is closed.

b) Determine the current in each resistor a very long time after the switch is closed.

c) Determine the voltage across the capacitor a very long time after the switch is closed.

After the switch has been closed for a very long time, it is reopened.

d) Determine the initial current I_{0}through the 100 ohm resistor, as a function of time after the switch is reopened.

e) Determine I(t), the current through the 100 ohm resistor, as a function of time after the switch is reopened.

f) How long after the switch is reopened does the charge on the capacitor fall to 10% of its fully charged state?

2. Relevant equations

V=IR

I through a capacitor is I = Cdv/dt = Q/C

Kirchoff's Loops Rules

3. The attempt at a solution

a) Immediately after the switch is closed, the capacitor behaves ls a short circuit and hence no current flows through the 100 ohm resistor.

I in the 200 ohm resistor = V/R=15V/200ohms=.075A

b) long after the switch is closed, the capacitor is fully charged and behanves as an open circuit. All of the current passes through both resistors.

Left Loop Clockwise:

15V-200ΩI_{1}-100ΩI_{1}=0

Right Loop Counter clockwise: Q/C-100ΩI_{1}-0

I_{1}is the only current passing through both the resistors

I= 20A

as for the rest of the parts, I want to make sure I get A and B right before I move on.

**Physics Forums - The Fusion of Science and Community**

# Another DC Circuit (But more complicated with a SWITCH and Capacitor!)

Know someone interested in this topic? Share a link to this question via email,
Google+,
Twitter, or
Facebook

Have something to add?

- Similar discussions for: Another DC Circuit (But more complicated with a SWITCH and Capacitor!)

Loading...

**Physics Forums - The Fusion of Science and Community**