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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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Answer» 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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