The resistance of platinum wire at is 2 and 6.8 at . The temperature coefficient of resistance of the wire is [2023]

Question

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 [2023]

Smart Achievers · Accepted Answer

(1)

Given, $R_{0} = 2 Ω$ at $T_{1} = 0 ° C$ and $R = 6.8 Ω$ at $T_{2} = 80 ° C$

As, $R = R_{0} [1 + α (T_{2} - T_{1})]$

$6.8 = 2 [1 + α (80 - 0)] \Rightarrow 6.8 = 2 + 160 α$

$α = 0.03 or 3 \times 10^{- 2} ° C^{- 1}$

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