All household socket have two wires.Plese do not mention grounding, the ground would act as de-facto second wire
It would depend on the type of power. Three phase AC which is commonly used to transmit power cannot be transmitted in one wire. Single phase ungrounded AC could be transmitted in one wire. DC can also be transmitted in one wire.
anyway you need two wires.. that's standard.. and if you can .. evan the ground.. good luck!
Yes, to a limited extent. That is the idea behind a capacitor. You quickly build up enough charge, though, that the current stops.
This kind of depends on how you define the one wire. I can take a single wire and run it from the pos. pole on a battery over to the neg. pole, current will flow. If I shoot a model rocket with a single wire attached into a thunder cloud, current will flow. The problem comes in when you want to actually place a load into the circuit and make that current do some work. There HAS to be a return line, or ground, otherwise the circuit is open and no current can flow.
You don't need any wires at all. It can be done easily with electromagnetic waves. But since it can be done even more easily with two wires, we prefer the two wire method. One wire would be as good as no wires, so that's just a waste. :-)
