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We prefer magainin wire to make a potent...

We prefer magainin wire to make a potentiometer. Why do not we use copper instead ?

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Managanin is a material with high resistivity and a low temperature coefficient of resistance. Thus the resistance of managanin does not change much with the change in the temperature . On the other hand, copper has a low specific resistance or resistivity and the temperature coefficient to measure the emf of a cell, because it uses null point method to measure the potential difference.
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