Question

there are two metallic wires of the same thickness made from iron and silver if the length or iron wire is 12 cm what should be the length of silver wire which is equal to the resistance of iron wire ?
data: resistance of iron =10*10^-8​

Answer 1

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Length=7.5 cm

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Length of the Iron wire = 12 cm

Resistance of Iron wire = Resistance of Silver Wire

Also,

Area of cross section, A of Iron wire = Area of cross section of Silver wire

Resistivity of Iron = 10 x 10⁻⁸ Ωm

Resistivity of Silver = 16 x 10⁻⁸ Ωm

So,

We know that the Resistance of the wire is given by,

So,

Therefore the length of silver wire is 7.5cm