Question

When a liquid is heated in a glass vessel, its coefficient of apparent expansion is $1.03\times {10}^{-3}/{}^{\circ }C$. When the same liquid is heated in a copper vessel, its coefficient of apparent expansion is $1.006\times {10}^{-3}/{}^{\circ }C$. If the coefficient of linear expansion of copper is $17\times {10}^{-6}/{}^{\circ }C$, then the coefficient of linear expansion of glass is:

• A. $9\times {10}^{-6}/{}^{\circ }C$
• B. $27\times {10}^{-6}/{}^{\circ }C$
• C. $10\times {10}^{-4}/{}^{\circ }C$
• D. $8.5\times {10}^{-4}/{}^{\circ }C$

Answer 1

The correct option is A $9\times {10}^{-6}/{}^{\circ }C$

Coefficient of apparent expansion is the difference between the coefficient of volume expansion of liquid and that of vessel.

Thus, ${\gamma }_a={\gamma }_l-{\gamma }_v$

$⟹1.03\times {10}^{-3}={\gamma }_l-3{\alpha }_{glass}$

And also, $1.006\times {10}^{-3}={\gamma }_l-(3\times 17\times {10}^{-6})$

Eliminating ${\gamma }_l$ gives,

${\alpha }_{glass}=9\times {10}^{-6}{/}^{\circ }C$