JEE Main & Advanced Physics Thermometry, Calorimetry & Thermal Expansion Question Bank Self Evaluation Test - Thermal Properties of Matter

  • question_answer
    Three liquids of equal volumes are thoroughly mixed. If their specific heats are \[{{\operatorname{s}}_{1}},\,\,{{s}_{2}},\,\,{{s}_{3}}\] and their temperatures \[{{\theta }_{1}},{{\theta }_{2}},{{\theta }_{3}}\] and their masses \[{{\operatorname{m}}_{1}},\,\,{{m}_{2}},\,\,{{m}_{3}}\] respectively, then the final temperature of the mixture is

    A) \[\frac{{{s}_{1}}{{\theta }_{1}}+{{s}_{2}}{{\theta }_{2}}+{{s}_{3}}{{\theta }_{3}}}{{{m}_{1}}{{s}_{1}},\,\,{{m}_{2}}{{s}_{2}},\,\,{{m}_{3}}{{s}_{3}}}\]

    B) \[\frac{{{m}_{1}}{{s}_{1}}{{\theta }_{1}}+{{m}_{2}}{{s}_{2}}{{\theta }_{2}}+{{m}_{3}}{{s}_{3}}{{\theta }_{3}}}{{{m}_{1}}{{s}_{1}},\,\,{{m}_{2}}{{s}_{2}},\,\,{{m}_{3}}{{s}_{3}}}\]

    C) \[\frac{{{m}_{1}}{{s}_{1}}{{\theta }_{1}}+{{m}_{2}}{{s}_{2}}{{\theta }_{2}}+{{m}_{3}}{{s}_{3}}{{\theta }_{3}}}{{{m}_{1}}{{\theta }_{1}},\,\,{{m}_{2}}{{\theta }_{2}},\,\,{{m}_{3}}{{\theta }_{3}}}\]

    D) \[\frac{{{m}_{1}}{{\theta }_{1}}+{{m}_{2}}{{\theta }_{2}}+{{m}_{3}}{{\theta }_{3}}}{{{\operatorname{s}}_{1}}{{\theta }_{1}},\,\,{{\operatorname{s}}_{2}}{{\theta }_{2}},\,\,{{\operatorname{s}}_{3}}{{\theta }_{3}}}\]

    Correct Answer: B

    Solution :

    [b] Let lost temperature is \[T{}^\circ C\]then \[{{m}_{1}}{{s}_{1}}{{T}_{1}}+{{m}_{2}}{{s}_{2}}{{T}_{2}}+{{m}_{3}}{{s}_{3}}{{T}_{3}}\] = released energy =\[{{m}_{1}}{{s}_{1}}{{T}_{1}}+{{m}_{2}}{{s}_{2}}{{T}_{2}}+{{m}_{3}}{{s}_{3}}{{T}_{3}}\]= energy taken \[\Rightarrow T=\frac{{{m}_{1}}{{s}_{1}}{{T}_{1}}+{{m}_{2}}{{s}_{2}}{{T}_{2}}+{{m}_{3}}{{s}_{3}}{{T}_{3}}}{{{m}_{1}}{{s}_{1}}+{{m}_{2}}{{s}_{2}}+{{m}_{3}}{{s}_{3}}}\]


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