To what value would you have to raise the temperature of a copper wire (originally at 20 ∘C) to increase its resistance by 14 %?

55.62 °C increase in temperature

Explanation:

Copper has a Temperature Coefficient of at near room temperature of + 0.393 percent per degree C increase in temperature.

Hence to increase the resistance by 14 % =

14/0.393 = 35.62 °C increase in temperature

That is if the temperature increases 35.62 °C, the resistance will increase 0.393%*35.62 or 14 %.

Hence the new temperature will be 35.62 + 20 = 55.62 °C