Question

The potentiometer is more appropriate for measuring potential difference than a voltmeter because

• A. the resistance of voltmeter is high
• B. the sensitivity of a potentiometer is higher than that of voltmeter
• C. the resistance of potentiometer wire is very low
• D. the potentiometer does not draw any current from the unknown source of emf

Answer 1

The correct option is D the potentiometer does not draw any current from the unknown source of emf

A voltmeter, when connected across two points, develops little current through itself due to the potential difference between the two points. This changes the actual circuit and hence an accurate reading is not obtained.

A potentiometer reading is based on finding an equipotential point such that no current flows. The circuit is not affected in such case and a more appropriate reading is obtained.