Potentiometer

The video tutorial explains the use of a potentiometer, a device similar to a meter bridge but with a longer resistance wire for greater accuracy. It describes how a standard cell maintains a constant current, allowing the potentiometer to compare the EMF of two cells using a two-way key and Kirchoff's loop rule. The tutorial also covers measuring the internal resistance of a cell by connecting it across a resistance box. The potentiometer's advantage is that it draws no current from the voltage source, making it unaffected by the source's internal resistance.

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