Final answer:
Two conducting paths from a voltage source to an electrical device are needed to complete an electrical circuit and allow the current to flow through the device.
Step-by-step explanation:
In order to operate an electrical device, two conducting paths from a voltage source are needed to complete an electrical circuit.
When a voltage source, such as a battery, is connected to an electrical device, it provides a potential difference between its terminals. This potential difference allows electric charges to flow through the device, creating a current. For the current to flow, there needs to be a complete path for the charges to travel from the positive terminal of the voltage source to the negative terminal.
By creating two conducting paths, one from the positive terminal and another from the negative terminal of the voltage source, the circuit is complete, allowing the current to flow through the device and operate it.