Question

When calibrated on the Celsius scale , the lower and upper fixed length of a thread are respectively 2.0cm and 10.0 cm from the bulb. What is the temperature of the room where the length of the thread is 8.0cm

Answer 1

$\begin{aligned} \dfrac{L_{b.p} - L_{i.p}}{L_{t} - L_{i.p}}&=\dfrac{T(b.p) - T(i.p)}{T - T(i.p)}\\ \\ \dfrac{10-2}{8 -2}&=\dfrac{100-0}{T-0}\\ \\ \dfrac{8}{6}&=\dfrac{100}{T}\\ \\ T &= \dfrac{6×100}{8}\\ &= 75°C \end{aligned}$