A platinum resistance thermometer wire has a resistance of 5 ohms at \(0^{\circ} C\) and \(5.5\) ohms at \(100^{\circ} C\). Calculate the temperature of the wire when the resistance is \(5.2\) ohms
A. \(80^{\circ} C\) B. \(60^{\circ} C\) C. \(40^{\circ} C\) D. \(10^{\circ} C\)
Correct Answer: C
Explanation
By interpolation $$ \begin{aligned} \frac{100-0}{x-0} &=\frac{5.5-5}{5.2-5} \\ \frac{100}{x} &=\frac{0.5}{0.2} \\ x &=\frac{100 \times 0.2}{0.5} \\ x &=40^{\circ} C \end{aligned} $$
