JEE Main & Advanced Physics Wave Mechanics Question Bank Interference and Superposition of Waves

  • question_answer
    The amplitude of a wave represented by displacement equation  \[y=\frac{1}{\sqrt{a}}\sin \omega t\pm \frac{1}{\sqrt{b}}\cos \omega t\]  will be [BVP 2003]

    A)            \[\frac{a+b}{ab}\]              

    B)            \[\frac{\sqrt{a}+\sqrt{b}}{ab}\]

    C)            \[\frac{\sqrt{a}\pm \sqrt{b}}{ab}\]                                

    D)            \[\sqrt{\frac{a+b}{ab}}\]

    Correct Answer: D

    Solution :

                       \[y=\frac{1}{\sqrt{a}}\sin \omega t\pm \frac{1}{\sqrt{b}}\sin \left( \omega t+\frac{\pi }{2} \right)\]            Here phase difference =\[\frac{\pi }{2}\]\[\therefore \] The resultant amplitude = \[\sqrt{{{\left( \frac{1}{\sqrt{a}} \right)}^{2}}+{{\left( \frac{1}{\sqrt{b}} \right)}^{2}}}=\sqrt{\frac{1}{a}+\frac{1}{b}}=\sqrt{\frac{a+b}{ab}}\]


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