How does electricity flow in a conductor? It is because of the potential difference across the conductor. How is this potential difference measured? It is measured with a device called voltmeter.
Our life is incomplete without electricity. Whatever we do, be it watching television, working on laptop, using tube lights for light, using microwaves, charging batteries for our cars or vehicles, all of these need electricity. At the end of the month, we get an electricity bill which we need to pay. We need to pay for the amount of electricity we have used. How do we measure the amount of electricity used by us? We use ammeter for this purpose.