JCECE Medical JCECE Medical Solved Paper-2014

  • question_answer
    A lead bullet of unknown mass is fired with a speed of 180 ms~1 into a tree in which it stops. Assuming that in this process two-third of heat produced goes into the bullet and one-third into wood. The temperature of the bullet rises by

    A)  \[140{{\,}^{o}}C\]

    B) \[106{{\,}^{o}}C\]

    C)  \[90{{\,}^{o}}C\]

    D) \[100{{\,}^{o}}C\]

    Correct Answer: C

    Solution :

     Specific heat of lead\[=0.120\,J/g\,{{\,}^{o}}C\] \[=120\,J/kg\] The two-third of heat produced goes into the bullet. So. \[m\times s\times \Delta \theta =\frac{2}{3}\times \frac{1}{2}m{{v}^{2}}\] \[\Delta \theta =\frac{{{v}^{2}}}{3\times s}=\frac{180\times 180}{3\times 120}=90{{\,}^{o}}C\]


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