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

  • question_answer
    An ice block at \[0{}^\circ C\] and of mass m is dropped from height 'h' such that the loss in gravitational potential energy of block is exactly equal to the heat required to just completely melt the ice. Taking latent heat of fusion of ice \[=\text{ }80\text{ }cal/gm,\] acceleration due to gravity \[=\text{ }10\text{ }m/{{s}^{2}}\] and, mechanical equivalent of heat \[=\text{ }4.2\text{ }J/Cal\]. The value of 'h' is

    A) 8 m                  

    B) 8 km

    C) 33.6 m             

    D) 33.6 km

    Correct Answer: D

    Solution :

    From given statement
    \[\text{mgh = mL}\]or \[\text{gh = L}\]
    or \[10\times h=\frac{80\times 4.2}{{{10}^{-3}}}\]
    or \[h=33.6\times {{10}^{3}}\text{meter =33}\text{.6 km}\]


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