Solving RC Circuit Questions: How to Find Charge/Current

[joedirt]

Circuits question!?

A series RC circuit consists of a 550-µF capacitor (initially uncharged) and a 12-kOhm resistor. The combination is connected across a 12-V battery; 3.0 s later, what is

(a) the charge on the capacitor,

(b) the current in the resistor?


I really just want to know what equations I need to use.. I'm sure I can work it out knowing the right way to do it.

 

[diazona]

What equations do you know that concern RC circuits, or circuits in general?

 

[joedirt]

I don't know any that's way I'm asking for the equation/s. I know a little about the Kirchhoff's current laws.

 

[diazona]

That's fine, you can use Kirchoff's laws to solve the problem. How would you apply Kirchoff's loop rule to this circuit?

 

[paranormal]

I can provide you with the necessary equations and steps to solve this RC circuit question. The equations we will be using are:

1. Q = CV, where Q is the charge on the capacitor, C is the capacitance, and V is the voltage across the capacitor.

2. I = V/R, where I is the current in the resistor, V is the voltage across the resistor, and R is the resistance.

To find the charge on the capacitor, we first need to calculate the voltage across the capacitor. Since the capacitor is connected to a 12-V battery, the voltage across it will also be 12 V. So, using the first equation, we can write:

Q = (550 µF)(12 V) = 6.6 mC

Therefore, after 3.0 seconds, the charge on the capacitor will be 6.6 mC.

To find the current in the resistor, we can use the second equation:

I = (12 V)/(12 kOhm) = 1 mA

So, after 3.0 seconds, the current in the resistor will be 1 mA.

I hope this helps you in solving the RC circuit question. Remember to always use the appropriate equations and units in your calculations. Good luck!