kirchoffs laws essentially define the basic behavoir of voltage and current in a circuit (all the voltages arround a loop balance out and all the current that goes into a point must come out)
i'm not sure if the lp/A formula has a name but it is the standard way of calculating resistance (i belive you sparkies tend to work from tables of p/A for the standard cable sizes rather than dividing the value of p for your conductor material by the CAS yourselves though)
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