Question

An iron rod has a length of 70m when the temperature is 30°C. By how much will it expand when the temperature rises to 40°C (Linear expansion of iron rod = 1.2×10^-5 per kelvin)

Answer 1

Given:

$l_0=70\:\rm cm$

$\alpha=1.2*10^{-5}\:\rm K^{-1}$

$\Delta t=10\:\rm K$

The thermal expansion is described by an equation

$$\Delta l=l_0\alpha\Delta t$$ $$\Delta l=\rm 70\: cm*1.2*10^{-5}\: K^{-1}*10\: K=0.0084\: cm$$