BHU PMT BHU PMT (Screening) Solved Paper-2009

  • question_answer
    If the momentum of a particle is increased by 20%, then its kinetic energy increases by

    A)  44%                                      

    B)  66%

    C)  80%                                      

    D)  30%

    Correct Answer: A

    Solution :

                     Energy \[E=\frac{{{P}^{2}}}{2m}\] If m is constant, then\[E\propto {{P}^{2}}\] \[\Rightarrow \]               \[\frac{{{E}_{2}}}{{{E}_{1}}}={{\left[ \frac{{{p}_{2}}}{{{p}_{1}}} \right]}^{2}}={{\left[ \frac{1.2p}{p} \right]}^{2}}=1.44\] \[\Rightarrow \]               \[{{E}_{2}}=1.44{{E}_{1}}={{E}_{1}}+0.44{{E}_{1}}\] or            \[{{E}_{2}}={{E}_{1}}+44%\]of\[{{E}_{1}}\]ie, the kinetic energy will increase by 44%.


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