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# Current Electricity watch

1. Physics people..I need help here
A student sets up a potentiometer and finds that no meter where along the potentiometer wire contact is made,the galvanometer deflection is always in the same direction and is impossible to obtain a zero current reading.give reasons for this phenomenon ..
Physics people..I need help here
A student sets up a potentiometer and finds that no meter where along the potentiometer wire contact is made,the galvanometer deflection is always in the same direction and is impossible to obtain a zero current reading.give reasons for this phenomenon ..
One end of the potentiometer (the end not connected to the e.m.f. source) is left open circuit (infinite resistance). There is no path for current to flow other than through the galvanometer which must therefore always deflect in the same direction irrespective of the wiper position.

Think of the potentiometer as a potential divider. With one end open circuit, the divider is made up of a finite resistance (e.m.f.) source end, and an infinite resistance (open circuit end). Therefore the p.d. developed across the track will always be equal to the source e.m.f. and hence the wiper will always be at the source e.m.f. potential irrespective of the finite resistance of the potentiometer.

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Updated: March 14, 2016
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