Question

Name the device used to measure electric current and potential in the circuit .How are they connected?

Answer 1

Hint: The device used to measure the electric current is familiar to its SI unit (ampere). And the device used to measure potential difference is the same as its SI unit( volt). Also the device used to measure potential should be connected such that it has the same potential difference across the resistor.

Complete answer:
The device used to measure electric current is called an ammeter .And the device used to measure voltage is called a voltmeter.Lets see how these devices should be connected in a circuit.
Ammeter: Generally resistance ammeter is very small and hence it has to be connected such that minimum resistance is passed through It and the current flowing through it is the same. If it is connected in parallel it would draw a lot of current and get damaged. Hence it is connected in series.

Voltmeter: It is connected in parallel because the devices in parallel connection have the same potential difference. It has high resistance and hence the amount of current passing through it is also very less. Therefore the current doesn’t vary even when voltmeter is attached to it.

Hence the conclusion is that the device that measures electric current is Ammeter and the device that measures potential in the circuit is voltmeter. The ammeter should be connected in series and voltmeter should be connected in parallel.

Note: If the ammeter is connected in parallel the net resistance of the circuit reduces, and current is inversely proportional to resistance, hence more current passes through the ammeter and it gets damaged. When a voltmeter is connected in series it behaves like a normal resistor because it is a high resistance device and hence allows no current to pass through it.