Question

why two wirws are used for carrying current instead of one wire?​

Answer 1

This is a very common misunderstanding. The explanation is that flow of charge is NOT flow of energy. Charge and energy are separate, although interdependent in electricity. Charge is not delivered from the supply to the load. Instead, charge moves around a circuit. That’s why you need two wires - for the charge to travel all the way around to form a current. Without a circuit the current can’t flow.

Answer 2

Answer:

Charge and energy are separate, although interdependent in electricity. Charge is not delivered from the supply to the load. Instead, charge moves around a circuit. That's why you need two wires - for the charge to travel all the way around to form a current.