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Resistance of a uniform metallic conductor is directly proportional to the length (l) and inversely proportional to the area of cross-section.

i.e. R

R

Or R =

ρ is constant of proportionality and is known as electrical resistivity of the material

When length of wire is doubled, the current decreases because Resistance of a uniform metallic conductor is directly proportional to the length (l) and according to Ohm’s law, Resistance is inversely proportional to the current and therefore when the length of wire is increased, there is decrease in the value of current.