First of all it is important to be aware of the functionality of the voltmeter. The voltmeter is indeed a device that is responsible for the measurement of the potential difference i.e. pd across the two points within a given circuit. For that it is connected in parallel specifically.Complete step by step answer:
First of all we need to be aware of the processes conducted by the voltmeter and in the circuit. Voltmeter is a device responsible for the measurement of the potential difference between any two given points in the circuit.
To do this process they need to be connected using two wires from the electrical system. This is done by connecting one wire to circuit and one of its ends to the node of the voltmeter and similarly for the other half.
Now in the process of the voltmeter there are specific conditions, and they are as follows :
A) As the voltmeters are connected in parallel so if they would have low resistance then they will deviate more current hence the resistance should be quite high for that.
$I = V/R$
Then $R \approx \infty $ so $I \approx 0$
So the option A is wrong and B is also wrong.
B) As mentioned earlier the voltmeter have very high resistance as compared to the device they are connected along, therefore the voltmeter can’t be in series as then it would nearly make the circuit short-circuited.
So it option C is wrong and D is correctTherefore the right option is D. Note:
Voltmeter basically measures the potential difference between two points in a given circuit, when it is connected in parallel to the two points across which we want to find the voltage.