How Do You Calculate Net Resistance and Current Flow in These DC Circuits?

[scrubber]

Homework Statement

http://postimg.org/image/8oweasluj/
Each rectangle in the figures represents a resistor with resistance=2.9kΩ.

a) What is the net resistance of the circuit of Fig 1 connected to the battery? Each resistance has R=2.9 kΩ.

b) What is the current flowing into the junction c and the branch of ca from the battery?

c) If we replace the branch of bc with a 12V battery as Fig 2 shows and Vb>Vc, what is the current flowing into the branch of CA?

The Attempt at a Solution

a) Is the circuit in Fig 1 equal to that of Fig 3 as below?
http://postimg.org/image/t5cwrllzt/

Thank you.

 

[Sumanth]

Yes, you can take it and solve it

 

[scrubber]

Yes, you can take it and solve it

Thank you so much! :D
I know part a then, just apply the parallel and series equations.

But for part b, does it mean that first I have to calculate the total current =It,
then apply Ic=It*(Rt-Rc/Rt), where Rt represents the total resistance?

 

[Sumanth]

No, just apply ohm's law

 

[Sumanth]

V=ir. R means effective resistance
"i"means total current through the cell.
And then divide current into the branches of circuit in corresponding ratios.

 

[scrubber]

V=ir. R means effective resistance
"i"means total current through the cell.
And then divide current into the branches of circuit in corresponding ratios.

I see! I understand now :D Thank you so much!
How about part c then?
Should I use Kirchhoff's Rule? But can Kirchhoff's Rule be applied if there's more than two loops?

 

[scrubber]

And in part b, the current flowing into junction c and branch ca would be the same then?
(Since the ratio of resistance are the same?)

 

[scrubber]

For part b, can I rather use V=IR to find out the current through branches directly after finding out the total current?

 

[Sumanth]

Kirchoff law can be applied separately to any number of loops and solve then separately to find currents