Question

A wire has a resistance of $10.5\Omega$ at ${21}^{o}C$ and $16.4\Omega$ at ${147}^{o}C$. Find the value of temperature coefficient of resistance.

Answer 1

Using the relation :
$R_2=R_1[1+\alpha (T_2-T_1]$
Here,
$R_1=10.5\Omega$ ; $T_1={21}^{\circ }C$
$R_2=16.4\Omega$; $T_2={147}^{\circ }C$
Putting the values in the equation,
$16.4=10.5[1+\alpha (147-21\left)\right]$
Therefore,

$\alpha =4.45\times {10}^{-3}{C}^{-1}$