The temperature coefficient of resistance of a wire is 0.00125 per ^oC. At 300K its resistance is 1 ohm. The resistance of the wire will be 2 ohm at

Given, R₁ = 1$\Omega$, R₂ = 2$\Omega$, t₁ = 300K = 27^o, t₂ = ?

We have, $\begin{array}{rcl}\mathrm{\alpha } & =& \frac{({\mathrm{R}}_2 - {\mathrm{R}}_1)}{({\mathrm{R}}_1{\mathrm{t}}_2 - {\mathrm{R}}_2{\mathrm{t}}_1)}\\ & \Rightarrow & 0.00125 = \frac{(2-1)}{(1\times {\mathrm{t}}_2 - 2\times 27)}\\ & =& \frac{1}{({\mathrm{t}}_2- 54)}\\ & \Rightarrow & ({\mathrm{t}}_2- 54) = \frac{1}{0.00125} = 800\\ & & \end{array}$

                                        $\Rightarrow {\mathrm{t}}_2 =854$

Hence, ${\mathrm{t}}_{2 = }(854 + 273) \mathrm{K}= 1127\mathrm{K}$