A wire has a resistance of 7.5 Ohms at 22°C and 15.7 Ohm at 175°C. Determine the temperature coefficient of resistance of the material.

7.1 x 10-3 °C-1 2.5 x 10-9 °C-1 7.1 x 10-5 °C-1 2.5 x 10-5 °C-1

7.1 x 10-3 °C-1

Temperature coefficient : α = \(\frac{R - R_{o}}{θR_{o}}\) R = 15.7 Ohms ; Ro = 7.5 Ohms ; θ = (175 - 22) °C-1 = 153 °C-1 α = 7.1 x 10-3 °C-1