Question

What will happen if a voltmeter is connected in a series?

Answer 1

Hint: We know that the resistance of a voltmeter is nearly infinite. Then we have to use Ohm’s Law of electricity. So, by putting the resistance of the voltmeter as infinite in Ohm’s Law we will find the current flowing in the circuit.

Complete step by step answer:
A voltmeter is a device which is used to measure the potential difference in a circuit. Its units are in volt. A voltmeter is always connected in parallel to the circuit. But the question asks here to find the outcome if it is connected in series.
We know that a voltmeter possesses a very high resistance within itself. If it is connected in series, the cumulative resistance of the circuit will become infinite.
Now according to Ohm’s law,
$V=IR$ where $V$ is the potential difference, $I$ is the current flowing in the circuit and $R$is the resistance in the circuit.
So, by cross-multiplication we find,
$I={\displaystyle \frac{V}{R}}$
Now, if the resistance is infinite then,
$I={\displaystyle \frac{V}{\mathrm{\infty }}}=0$
It is clear that if the resistance is infinite then current $I$is$0$.
So, when a voltmeter is connected in series with the circuit then no current flows through the circuit.
Additional information: As the term resistance comes into play quite often, we must understand what resistance is. Resistance refers to the obstruction or opposing force that restricts the flow of current in the circuit.

Note: It must be noted that if there is less resistance in a voltmeter then the measure of voltage would be inaccurate. Because, as it is connected in parallel more current would draw towards it and hence there would be more voltage. This is the reason why there is more resistance in voltmeter to restrict the flow of current towards itself and accurately measure the potential difference in the circuit.