Question

A potentiometer is an ideal device for measuring potential difference because
\[\left. A \right)\] It uses a sensitive galvanometer
$\left. B \right)$ It is an elaborate arrangement
$\left. C \right)$ It has a long wire hence heat developed is quickly radiated
$\left. D \right)$ It does not disturb the potential difference it measures

Answer 1

Hint: A potentiometer is a device which measures potential difference, a potentiometer works on the principle of Wheatstone bridge in which four resistors and a galvanometer are connected in an arrangement.

Complete answer:
A potentiometer does have a galvanometer but its sensitivity does not make the potentiometer an ideal device for measuring potential difference. A potentiometer basically is a Wheatstone bridge, when the resistors are connected in a particular way such that no current flows through the galvanometer this condition is called balanced Wheatstone bridge. In a condition of balanced Wheatstone bridge, we can measure potential difference about any known resistance. In any other device used for measuring potential difference say, voltmeter current passes through the voltmeter, so loss of current occurs at voltmeter so the reading of potential difference of voltmeter may have some error in it, but unlike potentiometer no current flows through galvanometer hence no current loss so the potential difference it reads is free from any errors because while taking reading it has not disturbed the potential difference itself which is being measured.

A potentiometer is an ideal device for measuring potential difference because It does not disturb the potential difference it measures.

So, the correct answer is “Option D”.

Additional Information:
Galvanometer is a device which is used to know the presence of current, to measure the value of current flowing we use another device called ammeter which is always connected in series in a circuit because it has a very low resistance it can easily measure most of the current flowing through it.

Note:
To find out potential difference from a potentiometer, one should know the values of resistances connected in a potentiometer because only by using the known value of resistance potential difference can be calculated across it.