So for problem 2, two things seem unclear to me, is 120 rms only related to load 2 and is it the main voltage or is it like Vout of that part? How does Vs play a part in this?

And whilst voltage is the same in a parallel circuit, why does the 120 V act as the main voltage when trying to find I=S/V in both of these loads? Shouldn't it be Vs ?

Secondly, when to calculate Vs: can we use another way other than using KVL?

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