Question

The table gives the initial length $l_0$, change in temperature $\Delta T$ and change in length $\Delta l$ of four rods. Which rod has greatest coefficient of linear expansion

• A. $A_1$
• B. $A_2$
• C. $A_3$
• D. $A_4$

Answer 1

The correct option is D $A_4$

${\alpha }_1=\frac{\Delta l}{l_0\Delta T}=\frac{1\times {10}^{-3}}{1\times 100}={10}^{-5}$

${\alpha }_2=\frac{2\times {10}^{-3}}{1\times 100}=2\times {10}^{-5}$

${\alpha }_3=\frac{3\times {10}^{-3}}{1.5\times 50}=4\times {10}^{-5}$

${\alpha }_4=\frac{4\times {10}^{-3}}{2.5\times 20}=8\times {10}^{-5}$