Q24Short answer
What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads 5 A. The reading of the ammeter decreases to half when the length of the wire is doubled. Why? 94 E XEMPLAR P ROBLEMS – SCIENCE
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Hint— Use the formula R = ρ . Also, V = R I. R is doubled while V remains unchanged. Hence current becomes .