An electric current can flow in the wire from one end ... The bigger the difference in energy, the bigger the potential difference. For example, 230 V is a bigger potential difference than 12 ...

This makes it difficult for electrical current to flow through them ... Although most non-metals are poor conductors, graphite is an example of a non-metal which is a good electrical conductor.

Scientists worked with electricity long before they understood that current was made of electrons. The cathode tube was a prime example. By switching on some voltage, scientists could make ...