# What is electrical resistivity ? In a series electrical circuit comprising a resistor made up of a matallic wire, the ammeter reads 5 A. The reading

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What is electrical resistivity ? In a series electrical circuit comprising a resistor made up of a matallic wire, the ammeter reads 5 A. The reading of the ammeter decreases to half when the length of the wire is doubled. Why ?

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As R = (rho l)/(A), when l is doubled, R is also doubled.
Since I = (V)/(R ), when R is doubled (V remaining unchanged), I becomes I//2.

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