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How can we select the resistance of the driver cell and length of the wire for a potentiometer?

How can we select the resistance of the driver cell and length of the wire for a potentiometer?

Grade:12

1 Answers

Arun
25758 Points
4 years ago
Potentiometer is a device used to measure the internal resistance of a cell, to compare the e.m.f. of two cells and potential difference across a resistor. It consists of a long wire of uniform cross sectional area and of 10 m in length. The material of wire should have a high resistivity and low temperature coefficient.  The wires are stretched parallel to each other on a wooden board. The wires are joined in series by using thick copper strips.
 
Potential gradient is given by,
( σ = V / L )
As length of the wire (L) is more, small will be the magnitude  of σ  and we  have more accuracy in measurement of potential difference with the help of potentiometer
 

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