The resistance of platinum wire at 0°C is 2 Ω and 6.8Ω at 80°C . The temperature coefficient of resistance of the wire is :

$R=R_0[1+\alpha \mathrm{\Delta }\theta ]$
Here, R is resistance at 80° C,
R₀ is resistance at 0° C,
α is temperature coefficient of resistance.
$\begin{array}{l}6.8=2[1+80\alpha ]\\ 3.4-1=80\alpha \\ \alpha =3\times {10}^{-2}{/}^{\circ }\mathrm{C}\end{array}$