The resistance of platinum wire at $0^{\circ}\,C$ is $2\,\Omega$ and $6.8\,\Omega$ at $80^{\circ} \,C$. The temperature coefficient of resistance of the wire is :
NEET 2023, Medium
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$R _{ T }= R _0\left[1+\alpha\left( T - T _0\right)\right]$
$6.8=2[1+\alpha(80-0)]$
$\alpha=\frac{2.4}{80}=0.03 /{ }^{\circ}\,C =3 \times 10^{-2} /{ }^{\circ}\,C$
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