Question

A platinum wire has a resistance of $10\Omega$ at $0^{\circ }C$ and $20\Omega$ at ${273}^{\circ }C$. Find the value of temperature coefficient of platinum.

• A. $\frac{1^{\circ }}{273}{C}^{-1}$
• B. $\frac{1^{\circ }}{273}{K}^{-1}$
• C. $\frac{1^{\circ }}{546}{C}^{-1}$
• D. $\frac{1^{\circ }}{546}{K}^{-1}$

Answer 1

The correct option is A $\frac{1^{\circ }}{273}{C}^{-1}$

$R_o=10\Omega$
$R_t=20\Omega$
$t={273}^{\circ }C$
$R_o=R_t(1+\alpha t)$
$\alpha =\frac{R_t-R_o}{R_{o}t}$
$\alpha =\frac{20-10}{10\times 273}={\frac{1}{273}}^{\circ }{C}^{-1}$