The resistance of platinum wire at 0 ° C is 2 Ω and 6 . 8 Ω at 80 ° C . The temperature coefficient of resistance of the wire is:NEET 2023 (All India)

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The variation of resistance of a conducting metal with temperature is given by
$R_{T} = R_{0} (1 + α (T_{2} - T_{1})) . . . (1)$
Substitute the values of the known parameters into equation (1) and solve to calculate the required temperature coefficient.
$\begin{array}{rcl} 6.8 Ω & = & 2 Ω \times (1 + α (80 - 0) ° C) \\ \Rightarrow & 1 + 80 α = 3.4 \\ \Rightarrow & 80 α = 2.4 \\ \Rightarrow & α = 3 \times 10^{- 2} C^{- 1} \end{array}$

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