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

  • question_answer
    The tempertaure of equal masses of three different liquids A, B and C are \[12{}^\circ C, 19{}^\circ C\] and \[28{}^\circ C\] respectively. The temperature when A and B are mixed is \[16{}^\circ C\] and when B and C are mixed is \[23{}^\circ C\]. The temperature when A and C are mixed is

    A) \[18.2{}^\circ C\]

    B) \[22{}^\circ C\]

    C) \[20.2{}^\circ C\]

    D) \[25.2{}^\circ C\]

    Correct Answer: C

    Solution :

    [c] Heat gain = heat lost \[{{C}_{A}}\left( 16-12 \right)={{C}_{B}}\left( 19-16 \right)\Rightarrow \frac{{{C}_{A}}}{{{C}_{B}}}=\frac{3}{4}\] and\[{{C}_{B}}\left( 23-19 \right)={{C}_{C}}\left( 28-23 \right)\Rightarrow \frac{{{C}_{B}}}{{{C}_{C}}}=\frac{5}{4}\] \[\Rightarrow \frac{{{C}_{A}}}{{{C}_{C}}}=\frac{15}{16}\]                              ?(i) If\[\theta \] is the temperature when A and C are mixed then, \[{{C}_{A}}(\theta -12)={{C}_{C}}(28-\theta )\] \[\Rightarrow \frac{{{C}_{A}}}{{{C}_{C}}}=\frac{28-\theta }{\theta -12}\]                      ?(ii) On solving equations (i) and (ii) \[\theta  = 20.2{}^\circ C\]


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