JEE Main & Advanced Physics Thermometry, Calorimetry & Thermal Expansion Question Bank Topic Test - Thermometry, Calorimetry & Thermal Expansion

  • question_answer
    A piece of metal weight 46 gm in air, when it is immersed in the liquid of specific gravity 1.24 at \[27{}^\circ C\] it weighs 30 gm. When the temperature of liquid is raised to \[42{}^\circ C\], the metal piece weighs 30.5 gm, specific gravity of the liquid at \[42{}^\circ C\] is 1.20, then the linear expansion of the metal will be

    A) \[3.316\,\times \,{{10}^{-5}}\,/{}^\circ C\]       

    B) \[2.316\,\times \,{{10}^{-5}}\,/{}^\circ C\]

    C) \[4.316\,\times \,{{10}^{-5}}\,/{}^\circ C\]       

    D) None of these

    Correct Answer: B

    Solution :

    Loss of weight at \[27{}^\circ C\] is
    \[=46-30=16={{V}_{1}}\times 1.24{{\text{ }\!\!\rho\!\!\text{ }}_{1}}\times g\]
    Loss of weight at \[42{}^\circ C\] is
    \[=46-30.5=15.5={{V}_{2}}\times 1.24{{\text{ }\!\!\rho\!\!\text{ }}_{1}}\times g\,....\left( ii \right)\]
    Now dividing (i) by (ii), we get
    \[\frac{16}{15.5}=\frac{{{V}_{1}}}{{{V}_{2}}}\times \frac{1.24}{1.2}\]
    But  \[\frac{{{V}_{2}}}{{{V}_{1}}}=1+3\alpha \left( {{t}_{2}}-{{t}_{1}} \right)=\frac{15.5\times 1.24}{16\times 1.2}=1.001042\]
    \[\Rightarrow 3\alpha \left( 42{}^\circ -27{}^\circ  \right)=0.001042\]
                \[\Rightarrow \alpha =2.316\times {{10}^{-5}}/{}^\circ C\]


You need to login to perform this action.
You will be redirected in 3 sec spinner