Question

The resistance of a wire of length 31.4 m
and diameter 1 mm is 20 2. Find the resistivity of
the material of the wire.​

Answer 1

Answer:

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Explanation:

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Answer 2

Solution 5 : Data : l = 31.4 m, d = 1mm = 1× 10 - 3 m

∴ r = d/2 = (1× 10-3m)/2 = 5× 10-4 m , R = 20 Ω , ρ = ?

R = ρ (l/A) = ρ (l/π r2)

∴ ρ = (Rπr2)/l

∴ ρ = 20Ω × 3.14 × (5× 10-4 m)2 / 31.4m

∴ ρ = 5× 10-7Ω .m

The resistivity of the material of the wire = 5 × 10-7 Ω m.