Question

Express which of the following setups can be used to verify Ohm's law?
A.
B.
C.
D.

Answer 1

Hint: Ohm’s law states that the amount of electric current through a conductor in a circuit is directly proportional to the potential difference applied across the conductor. The voltmeter measures the potential applied and the ammeter measures the electric current flowing through the conductor.

Complete step by step solution:
When a potential difference is applied across a conductor then the electric field is set up inside the conductor which applies force on the charge inside the conductor and hence the charge starts flowing in the direction of the electric field applied.

As we know from the definition of electric current that the magnitude of the electric current is the rate of flow of charge per unit time. And hence, the electric current can be measured using the device called an ammeter.

Ammeter records the amount of charge crossing the area per unit time, hence it should be connected in series in the circuit. So, in the Ohm’s law verification experiment the ammeter should be connected in series to the branch in which we need to measure the electric current.

The voltmeter measures the potential applied across the resistor. When electric current is flowing across the resistor then there is potential drop across the resistor which can be measured using the voltmeter. Hence, the voltmeter should be connected in parallel to across the resistor. In the figure, A the ammeter is connected in series and the voltmeter is connected in parallel. So, this setup can be used to verify Ohm's law.

Therefore, the correct option is A.

Note: In the experiment of Ohm’s law we assume the voltmeter and ammeter as ideal. So, when we record the measurement the recorded data deviates from the theoretical data of Ohm’s law of proportionality because voltmeter and ammeter also have resistance.