Uttarakhand PMT Uttarakhand PMT Solved Paper-2010

  • question_answer
    How many times more intense is a 90 dB sound than a 40 dB sound?

    A)  2.5   

    B)  5 

    C)  50  

    D)  10s

    Correct Answer: D

    Solution :

     \[90=10{{\log }_{10}}\left( \frac{{{I}_{2}}}{{{I}_{0}}} \right)\] \[\Rightarrow \] \[\frac{{{I}_{1}}}{{{I}_{0}}}={{10}^{4}}\]                      ...(i) Again, \[40=10{{\log }_{10}}\left( \frac{{{I}_{2}}}{{{I}_{0}}} \right)\] \[\Rightarrow \] \[\frac{{{I}_{2}}}{{{I}_{0}}}={{10}^{4}}\]                      ...(ii) From Eqs. (i) and (ii), we get \[\frac{{{I}_{1}}}{{{I}_{2}}}={{10}^{5}}\]


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