Manipal Engineering Manipal Engineering Solved Paper-2012

  • question_answer
    Oxygen is 16 times heavier than hydrogen. Equal volumes of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is

    A) \[\sqrt{8}\]                                        

    B) \[\sqrt{2/17}\]

    C) \[\sqrt{1/8}\]    

    D)        \[\sqrt{32/17}\]

    Correct Answer: B

    Solution :

    Let one mole of each gas has same volume as\[V\]. When they are mixed, then density of mixture is       \[{{\rho }_{\operatorname{mixture}}}=\frac{mass\,\,of\,\,{{O}_{2}}+mass\,\,of\,\,{{H}_{2}}}{volume\,\,of\,\,{{O}_{2}}+volume\,\,of\,\,{{H}_{2}}}\]                  \[=\frac{32+2}{V+V}=\frac{34}{2V}=\frac{17}{V}\] Also,\[{{\rho }_{{{H}_{2}}}}=\frac{2}{V}\] Now, velocity\[v={{\left( \frac{\gamma p}{\rho } \right)}^{1/2}}\]or\[v\propto \frac{1}{\sqrt{\rho }}\]                  \[\frac{{{v}_{mixture}}}{{{v}_{{{H}_{2}}}}}=\sqrt{\left( \frac{{{\rho }_{{{H}_{2}}}}}{{{\rho }_{mixture}}} \right)}\]                             \[=\sqrt{\left( \frac{2/V}{17/V} \right)}=\sqrt{\left( \frac{2}{17} \right)}\]


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