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A wire has a resistance of 3.12 Ω at 30°C and a resistance 4.52 Ω at 100°C. The temperature coefficient of resistance of the wire is:

1. 0.008°C⁻¹
2. 0.0034°C⁻¹
3. 0.0025°C⁻¹
4. 0.0012°C⁻¹

Correct answer: 0.0034°C⁻¹

Solution

The temperature coefficient of resistance (α) is calculated using the formula: α = (R₂ - R₁) / [R₁ × (T₂ - T₁)]. Substituting the given values: R₁ = 3.12 Ω, R₂ = 4.52 Ω, T₁ = 30°C, T₂ = 100°C, we get α = (4.52 - 3.12) / [3.12 × (100 - 30)] = 0.0034°C⁻¹.

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