A wire 3.00 m long and .450 mm2 in cross-sectional area has a resistance of 41.0Ω at 20 degrees C. If its resistance increases to 41.4Ω at 29.0 C, what is the temperature coefficient of resistivity?

Answer 1

R = Ro + aRo (T - To).

R = 41 + a41 (29 - 20) = 41.4 Ohms,
41 + 41a * 9 = 41.4,
41 + 369a = 41.4,
369a = 41.4 - 41 = 0.4,
a = 0.4 / 369 = 1.084*10^-3 = 0.001084 = Temperature coefficient of resistivity.