Find the length of a wire of diameter 2 mm, and resistivity 1.66x 10^-7 Ωm and resistance 2Ω?
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Cross sectional diameter = 2 mm
So, Radius = 1mm = 10 ^ -3 m.
Area of cross section = π * (10 ^ -3)²
= π x 10 ^ -6 m²
Resistance = Resistivity x length / cross sectional area
In symbols: R = ρL / A
Therefore, L = AR / ρ
Length = 2 π *10 ^ -6) / 1.66 x 10 ^ -7
Length = 37.85 m (Ans)
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So, Radius = 1mm = 10 ^ -3 m.
Area of cross section = π * (10 ^ -3)²
= π x 10 ^ -6 m²
Resistance = Resistivity x length / cross sectional area
In symbols: R = ρL / A
Therefore, L = AR / ρ
Length = 2 π *10 ^ -6) / 1.66 x 10 ^ -7
Length = 37.85 m (Ans)
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