The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are $8 \Omega$ and $10 \Omega$ respectively. After inserting in a hot bath of temperature $400^{\circ} \mathrm{C}$, the resistance of platinum wire is :

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Aicharya · Accepted Answer

Given $R_0=8 \Omega, R_{100}=10 \Omega$ $\therefore \mathrm{R}_{100}=\mathrm{R}_0(1+\alpha \Delta \mathrm{T})$
Also, $R_{400}=R_0\left(1+\alpha \Delta \mathrm{T}^1\right)$ $\begin{aligned} & \therefore 10=8(1+\alpha \times 100) \Rightarrow 100 \alpha=\frac{1}{4} \\ & \therefore \mathrm{R}_{400}=8(1+400 \alpha)=8(1+1)=16 \Omega \end{aligned}$

The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point…

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