Physics Question: Generating Electricity

Question

Electrical appliances plug into the wall with a single plug, but a plug has at least two prongs (sometimes there is a third one, but the minimum is two). Why do you think that this is the case? Refer to what you know about closed circuits in your answer.

 

Please help me answer using physics terms.

Answer 1

You need to think of how the flow of electrons works.  In the United States we use direct current electricity.  This means that the electricity will flow in one direction and one direction only.  If you think of a circuit using a battery instead of a plug, imagine where the wires go on the battery.  Could it be this is the same for a plug?