RAJASTHAN ­ PET Rajasthan PET Solved Paper-2002

  • question_answer
    The amplitude of any damped oscillation becomes half in 1 min. After 3 s, its amplitude becomes\[\frac{1}{x}\] times of initial amplitude, then\[x\]is \[x\]

    A)  \[2\times 3\]            

    B)  \[{{2}^{3}}\]

    C)  \[{{3}^{2}}\]             

    D)  \[3\times {{2}^{2}}\]

    Correct Answer: B

    Solution :

     Amplitude of damped oscillation \[A={{A}_{0}}{{e}^{-\lambda t}}\] Here, \[\lambda =\]constant, t = time For   \[t=1\]min, \[\frac{{{A}_{0}}}{2}={{A}_{0}}{{e}^{-\lambda \times t}}\]\[\Rightarrow \]\[{{e}^{\lambda }}=2\] For   \[t=3\]min, \[A={{A}_{0}}{{e}^{-\lambda \times 3}}=\frac{{{A}_{0}}}{{{({{e}^{\lambda }})}^{3}}}=\frac{{{A}_{0}}}{{{2}^{3}}}\] \[\Rightarrow \] \[x={{2}^{3}}\]


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