Physics | TS EAMCET 2017 | Discussion Page

A wire has resistance of $3.1 \Omega$ at $30^{0} C$ and $4.5 \Omega$ at $100^{0} C$ . The temperature coefficient of resistance of the wire is

A) $0.0012^{0} C^{-1}$

B) $0.0024^{0} C^{-1}$

C) $0.0032^{0} C^{-1}$

D) $0.0064^{0} C^{-1}$

Option *

Given,

$t_{1}=30^{0}C$

$R_{1}=3.1 \Omega$

$t_{2}=100^{0} C$

$R_{2}=4.5 \Omega$

we know that,

temperature coefficient of resistance,

$\alpha=\frac{R_{2}-R_{1}}{R_{1}t_{2}-R_{2}t_{1}}=\frac{4.5-3.1}{(3.1)(100)-(4.5 \times 30)}$

= $\frac{1.4}{310-135}=\frac{1.4}{175}=0.008^{0} C^{-1}$

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