BCECE Medical BCECE Medical Solved Papers-2010

  • question_answer
    Two sound waves, each of amplitude A and frequency\[\omega \], superpose at a point with phase difference of \[\frac{\pi }{2}\]. The amplitude and frequency of the resultant wave are respectively

    A)  \[\frac{A}{\sqrt{2}},\frac{\omega }{2}\]

    B)  \[\frac{A}{\sqrt{2}},\omega \] 

    C)  \[\sqrt{2A},\,\,\frac{\omega }{2}\]

    D)  \[\sqrt{2A},\,\,\omega \]

    Correct Answer: D

    Solution :

    Let \[{{y}_{1}}=A\sin (\omega \,t)\] and \[{{y}_{2}}=A\sin \left( \omega \,t+\frac{\pi }{2} \right)\] Resultant amplitude                 \[{{R}^{2}}={{A}^{2}}+{{A}^{2}}+2{{A}^{2}}\cos \left( \frac{\pi }{2} \right)\]                 \[{{R}^{2}}=2{{A}^{2}}+2{{A}^{2}}\times 0\] \[\Rightarrow \] \[R=\sqrt{2}\,\,A\] However, both will have the same frequency on superimposing.


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