Potentiometer :
A potentiometer is a linear conductor of uniform cross section with a steady current set up in it. This maintains a uniform potential gradient along the length of the wire. Any potential difference which is less than the potential difference maintained across the potentiometer wire can be measured with this device.
`I=epsilon/(R+r)` , `V_A-V_B= epsilon/(R+r) * R`
The wire of potentiometer should have low expansion coefficient and high resistivity e.g. Manganin
`text(Potential gradient `(z)` :)`
Potential difference per unit length of wire `z=(V_A-V_B)/L= epsilon/(R+r) * R/L`
1) Potentiometer is an ideal voltmeter
2) Using potentiometer we can find Emf of cell , internal resistance of cell etc.
`I=epsilon/(R+r)` , `V_A-V_B= epsilon/(R+r) * R`
The wire of potentiometer should have low expansion coefficient and high resistivity e.g. Manganin
`text(Potential gradient `(z)` :)`
Potential difference per unit length of wire `z=(V_A-V_B)/L= epsilon/(R+r) * R/L`
1) Potentiometer is an ideal voltmeter
2) Using potentiometer we can find Emf of cell , internal resistance of cell etc.