Question
Why is potentiometer preferred over a voltmeter for measuring emf?
✓
Answer
A voltmeter should ideally have an infinite resistance so that it does not draw any current from the circuit. However a voltmeter cannot be designed to have infinite resistance. A potentiometer does not draw any current from the circuit at the null point. Therefore, it gives more accurate measurement. Thus, it acts as an ideal voltmeter.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Obtain an expression for the capacitance of a parallel plate capacitor without a dielectric.
What is soft magnetic material?
Soft ferromagntic materials can be easily magnetized and demagnetized.
Soft ferromagntic materials can be easily magnetized and demagnetized.
Hysteresis loop for hard and soft ferramagnetic materials.
Magnetic field at a distance $2.4\ cm$ from a long straight wire is $16 \mu T.$ What must be current through the wire?
→In a potentiometer circuit. $E=2 V , r =2 \Omega_{ r } R _{\text {wire }}=10 \Omega_{ s } R _{\text {ext }}=1988 \Omega$ and $L =4 m$ (in the usual notation). What is the potential gradient along the wire?
→A piece of straight wire has mass 20 g and length 1m. It is to be levitated using a current of 1 A flowing through it and a perpendicular magnetic field B in a horizontal direction. What must be the magnetic of B?
Draw a neat labelled diagram illustrating spherical wavefronts corresponding to a diverging beam of light.
State Ampere's circuital law. Using Ampere's circuital law, obtain an expression for magnetic induction at any point due to a straight conductor carrying current.
Show that even as well as odd harmonics are present as an overtone in modes of vibration of the string.
Draw the circuit symbol for NPN and PNP transistors. What is the difference in the Emitter, Base, and Collector regions of a transistor?
The fundamental frequency of an air column in a pipe closed at one end is in unison with the third overtone of an open pipe. Calculate the ratio of the lengths of their air columns.