Question

Calculate the resistivity of a material of a wire 10 m long, 0.4 mm in diameter and having a resistance of 2ohm​

Answer 1

Resistivity = R*A / L

Diameter = 0.4 mm = 0.0004 m
Radius = 0.0002 m = 0.2 * 10^-3
Area = πr^2
= 22/7 * 0.2 * 10^-3 * 0.2 * 10^-3
= 22/7 * 0.4 * 10^-7
= 1.26 * 10^-7

Resistance = 2 ohms
Length = 10m

Resistivity = (2) * (1.26 * 10^-7) / 10
= 2.52 * 10^-8 ohm meter



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Answer 2

Answer:

resistivity = 6.28 × 10⁻⁷ Ωm

Explanation:

Diameter (d) = 0.4 mm

So, radius (r) = 0.4/2 = 0.2 mm

1 mm = 1/10 cm = 1/10 * 100 m = 10⁻³ m

Area (A) = πr² = 3.14 × (10⁻³)² = 3.14 × 10⁻⁶ m²

Length (L) = 10 m

Resistance (R) = 2 Ω

For further calculations, refer attachment.

Hence, resistivity = 6.28 × 10⁻⁷ Ωm