Finding current magnitude between two points in a circuit

[askor]

Homework Statement

Please give me a clue, I don't understand, how to find the magnitude of $I_{ab}$?

Homework Equations

The Attempt at a Solution

 

[cnh1995]

What have you tried so far? Are you familiar with KCL?

 

[CWatters]

Have you worked out the voltage on a/b?

 

[askor]

What have you tried so far? Are you familiar with KCL?

I am stuck. What is KCL? Is it Kirchoff's Current Law?

Have you worked out the voltage on a/b?

How?

 

[CWatters]

I am stuck. What is KCL? Is it Kirchoff's Current Law?

Yes.

Have you worked out the voltage on a/b?

How?

"a" and "b" are at the same voltage because they are connected together. To work out that voltage you can simplify the circuit and use the potential divider method. There are other ways.

Once you have that voltage you can calculate the currents through all the resistors. Then apply KCL at either a or b.

or you can just wade in and apply KCL from the outset.