Question 39 of 126
Two rods and of identical dimensions are at temperature . If is heated upto and upto then the new lengths are the same. If the ratio of the coefficients of linear expansion of and is then the value of is
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Answer: (A)
Change in length in both rods are same i.e.
$\begin{array}{l}
\frac{\alpha_{1}}{\alpha_{2}}=\frac{\Delta \theta_{2}}{\Delta \theta_{1}} \quad\left[\because \frac{\alpha_{1}}{\alpha_{2}}=\frac{4}{3}\right] \\
\frac{4}{3}=\frac{\theta-30}{180-30}
\end{array}$
$\begin{array}{l}
\frac{\alpha_{1}}{\alpha_{2}}=\frac{\Delta \theta_{2}}{\Delta \theta_{1}} \quad\left[\because \frac{\alpha_{1}}{\alpha_{2}}=\frac{4}{3}\right] \\
\frac{4}{3}=\frac{\theta-30}{180-30}
\end{array}$