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A wire has a resistance of 5.5 Ω at 19℃ and 21.5 Q at 200℃. Find the temperature coefficient of resistivity(α) of the material.

Correct answer: A. 0.016 per degree Celsius

  • A. 0.016 per degree Celsius
  • B. 32 per degree Celsius
  • C. 0.018 per degree Celsius
  • D. 0.00106 per degree Celsius

Explanation

According to the formula,R = Ro(1 +α ΔT)Or R = Ro + Roα ΔTOr R - Ro = Roα ΔTOr α = (R - Ro)/ RoΔTHere, R = resistance at given temperature, Ro = initial resistance.According to the given statement,Ro = 5.5R = 21.5ΔT = 200 - 19 = 181 (no need to convert to kelvin scale as the difference will still be same)Putting values,α = (21.5 - 5.5) / (5.5 x 181)α = 0.016 per degree celsiusHence, option A is the correct option.

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