RC Circuit Problem: Find I1, I2, I3 and Q

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 4K views
SamTsui86
Messages
30
Reaction score
0

Homework Statement



In Figure P18.50, suppose that the switch has been closed for a length of time sufficiently long enough for the capacitor to become fully charged. (R = 12.0 k, R2 = 17.0 k, R3 = 1.00 k, V = 9.70 V)

The picture is under attachment

a) Find the steady-state current in each resistor.
I1 = µA?
I2 = µA?
I3 = µA ?

(b) Find the charge on the capacitor.
µC ?


Homework Equations



R = V / I

q = Q e^(-t/RC)

The Attempt at a Solution



Well, since after the switch is closed, I figured all 9.7 V goes to the first resistor, so I used R = V / I to get the current for the first one. But it's wrong.
 

Attachments

  • p18-50alt.gif
    p18-50alt.gif
    4.9 KB · Views: 618
Physics news on Phys.org
It's wrong because there is a voltage divider formed with one of the other two resistors in the steady state. Which one? In the steady state, what is the voltage across the capacitor?