Question

A wire , 20m long is heated from a temperature of -5⁰c to 55⁰c,if the change in length is 0.020m, calculate the linear expansivity of the wire

Answer 1

Given:

$l_0=20\:\rm m$

$\Delta l=0.020\:\rm m$

\Delta t=60\:^\circ\rm C

The change in length of a wire at termal expansion is given by

$$\Delta l=l_0\alpha\Delta t$$

Hence, the linear expansivity of the wire

$$\alpha=\frac{\Delta l}{l_0\Delta t}=\frac{0.020}{20*60}=1.7*10^{-5}\:\rm K^{-1}$$