BHU PMT BHU PMT (Screening) Solved Paper-2008

  • question_answer
    In an adiabatic process wherein pressure is increased by\[\frac{2}{3}%\]. If\[\frac{{{C}_{p}}}{{{C}_{V}}}=\frac{3}{2},\]then the volume decreases by about

    A)  \[\frac{4}{9}%\]                                              

    B)  \[\frac{2}{3}%\]

    C)  \[4%\]                                 

    D)  \[\frac{9}{4}%\]

    Correct Answer: A

    Solution :

                     For an adiabatic process, \[p{{V}^{\gamma }}=\]constant (say C) Here      \[\gamma =\frac{{{C}_{p}}}{{{C}_{V}}}=\frac{3}{2}\] \[\therefore \]  \[p{{V}^{3/2}}=C\] \[\Rightarrow \]               \[\log p+\frac{3}{2}\log V=\log C\] \[\Rightarrow \]               \[\frac{\Delta \pi }{p}+\frac{3}{2}\frac{\Delta V}{V}=0\] \[\therefore \]  \[\frac{\Delta V}{V}=\frac{-2}{3}\frac{\Delta \pi }{p}\] \[\frac{\Delta V}{V}\times 100=\left( \frac{2}{3} \right)\left( \frac{\Delta \pi }{p}\times 100 \right)\]                 \[=-\frac{2}{3}\times \frac{2}{3}%=-\frac{4}{9}%\]           Thus, volume decreases by\[\frac{4}{9}%\].


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