The resistance of platinum wire at $0^{\circ} \mathrm{C}$ is $2 \Omega$ and $6.8 \Omega$ at $80^{\ci

Question

The resistance of platinum wire at $0^{\circ} \mathrm{C}$ is $2 \Omega$ and $6.8 \Omega$ at $80^{\circ} \mathrm{C}$. The temperature coefficient of resistance of the wire is\

Professor PC Thomas Classes · Answer

(a) : Given, $R_{0}=2 \Omega$ at $T_{1}=0^{\circ} \mathrm{C}$ and $R=6.8 \Omega$ at $T_{2}=80^{\circ} \mathrm{C}$\ As, $R=R_{0}\left[1+\alpha\left(T_{2}-T_{1}ight)ight]$\ $6.8=2[1+\alpha(80-0)]$\ $6.8=2+160 \alpha$\ $\alpha=0.03$ or $3 	imes 10^{-2}{ }^{\circ} \mathrm{C}^{-1}$\