Kirchoff's Laws

Hi. I'm really having problems understanding Kirchoff's Laws and my book isn't helping a lot. Can someone please explain how to do the following problem? My book shows a circuit with two loops and does the following (I don't think you need the drawing, since I can get from there to writing the equations; I'm just having a problem solving the equation): Apply junction rule to point A: I1 - I2 - I3 = 0 Apply the loop rule to loop 1 (let R = 100 ohms): 15V - I3R - I1R = 0 Apply the loop rule to loop2 (let R = 100 ohms): -9.0V - I2R + I3R = 0 Then the example just says "solve for I1, I2, and I3: I1 = 0.070, I2 = -0.010, I3 = 0.080" But I have no idea how to solve for I1, I2... click for more

Capacitors in series and parallel

Hi. Can someone please help me with the following problem? The problem shows a circuit with 2 capacitors in series on one side of the circuit: C1 = 8.2 micro-F, C2 = 22 micro-F. Together, those two capacitors are in parallel with C3, which = 15 micro-F. The question asks what is the energy stored in each capacitor, if the circuit is connected to a 9.0 V battery. The answers are: C1 = 1.8 x 10^-4 C2 = 6.6 x 10^-5 C3 = 6.1 x 10^-4 C3 is the only one I got the right answer for, using the equation U = (1/2)(C3)(V^2). The same equation doesn't work for the two capacitors in series. Can you tell me what I should be using for those two? Thank you.

Resistors

Hi. Can someone please help me with the following problem? I'll try to draw the circuit (with battery and 4 resistors), but I don't know if all the spacing will come out right. The /// are resistors. Basically, it's a circuit with a 15-V battery and 4 resistors. First you hit R1, which = 11 ohms. Then there are two paths -- path #1 contains R2=7.5 ohms; path #2 contains 2 resistors in series, R3=6.2 ohms and R4 = 12 ohms. R3 and R4 are in parallel with R3. R3=6.2 ohms | -----------------////-----| | | | | | | | / / 15V / R2=7.5 / R4=12 ohms | / o... click for more

conductors and dielectrics

Please see the attached file for full problem description. I'm having trouble with the topic of conductors and dielectrics.

conductors and dielectrics

Please see the attached file for full problem description. I'm having trouble with the topic of conductors and dielectrics.