A coil has a resistance of 10 Ω at 0 °C. Its temperature coefficient of resistance is 4.0 × 10⁻³ K⁻¹. What is its resistance at 50 °C?
Correct answer D. 12 Ω
Explanation
Rₜ = R₀(1 + αΔT) = 10 Ω × (1 + 4.0 × 10⁻³ × 50) = 10 × 1.2 = 12 Ω. The answer 2.0 Ω is only the increase, not the new resistance.
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