I have a couple of questions: 1]If we connect +ve terminal of DC battery to a bulb(using one wire) & another wire coming out from bulb is inserted in ground(earth) instead of connecting it to the -ve terminal of battery, will bulb glow? if yes, does it mean electrons in the wire flow into the earth? and how can bulb glow if electrons don't return to its source? If same thing is done with AC power supply do electrons moving out of the wire(where it is inserted in ground) into the ground & entering back in the wire as in AC, electrons move back & forth? my assumption is electricity is generated when electrons flow from source through the wire and come back to the source again. but how then grounding wire carries the current as it end in the ground? 2]We receive 1-phase AC voltage at home. AC polarity changes per complete cycle. But if we insert electrical tester in the wall socket, it's only one hole(live) in which tester light glows, in other hole(neutral) it doesn't. But since the polarity changes(each hole becomes +ve and -ve alternately) in other(neutral) hole also, tester light should glow, but it doesn't. Why?