Question

A rod of length 2m rests on smooth horizontal floor,. If the rod is heated from $0^{o}C$ to ${20}^{o}C$. Find the longitudinal strain developed?$(\alpha =5\times {10}^{-5/oC})$

• A. ${10}^{-3}$
• B. $2\times {10}^{-3}$
• C. Zero
• D. None

Answer 1

The correct option is B $2\times {10}^{-3}$

$\begin{array}{c}\text{rod of length}=2m\\ \text{placed on smooth horizontal floor, mean nó friction}\\ \text{heated from}{0}^{\circ }c+0coc\\ \text{.}\alpha =5\times {10}^{-5}\end{array}$

will be zero in this case - longitudinal strain developed will be zero in and it expand freely, because there in expanding.

$\begin{array}{cc}\Delta L\left(\text{expand}\right)& =L\alpha \Delta T\\ & =2\times 5\times {10}^{-5}\times (20-0)\\ \Delta L& =200\times {10}^{-5}m\end{array}$

$=2\times {10}^{-3}$ m

Hence option B is correct