Using the Mesh-Current method, a circuit can be described in b-(n-1) equations.
On the above circuit there are three resistors. An unknown current passes through each resistor (i.e. three unknown currents in total have to be estimated).
But on the above circuit there are two meshes with currents ia and ib. By applying Kirchoff's current law =>
By observing the above figure find:
On the above circuit there are 3 essential nodes and 5 essential branches.
Number of equation needed: b-(n-1)=3 equations
substituting (14) and (15) into (12) =>
ia = 3.04A
Since ia is the current in the 50V source =>
P(40V) = 50 x 3.04 = 152W
Since ic is the current in the 125V source =>
-2.35 x 125 = -293.75W
Note that ic was defined as flowing into the 125V source, then the source is actually providing power.
The current in the 6 ohm resistor is =>
=> voltage drop = 6 x 1.13 = 6.78V