Validity of interconnection in electric circuit

[Emilio]

Homework Statement

Homework Equations

P=Vi

The Attempt at a Solution

For part a, it looks like the dependent current source (4i₁) leads directly to i₁, with nothing that could change it. This would mean the interconnection is invalid, right? I can't tell if this circuit is in series or in parallel (is it both?), but I know independent voltage sources can't be parallel, and independent current sources can't be in series. I don't know which one would apply here though.

If the circuit is invalid, then I'm not sure how to find the total energy developed, but I guess it would be P=Vi at each node.

 

[NascentOxygen]

There are 2 independent current sources, together pushing how much current downwards to the lower node?

 

[Emilio]

Ah, so they push 240mA towards the lower node, with 4i₁ leaving the node. And that would make i₁=60mA.

So then lower node = 0 = 180mA+60mA-4i₁ = 180mA+60mA-4(60mA), which means it;s valid?

 

[NascentOxygen]

Next, address the voltage sources. Do they look okay here?

 

[Emilio]

At the top node, according to KVL, the net voltage should be 0=v1+v2. But here, the voltages are in the same direction, and are of different magnitudes so they don't cancel out. Does the dependent current source generate voltage as well? I thought it just changed the current.

 

[NascentOxygen]

Current sources adjust their terminal voltage to whatever is needed in order to force their designated current through the circuit.