BCECE Medical BCECE Medical Solved Papers-2002

  • question_answer
    If the equation of motion of standing wave is \[y=0.3\sin \,(314\,t-1.57\,x)\],the velocity of standing wave is :

    A)  400 unit       

    B)  250 unit

    C)  200 unit       

    D)  150 unit

    Correct Answer: C

    Solution :

    Key Idea : Standard equation of standing wave is \[y=a\sin \,(\omega \,t-kx)\]. When two identical transverse, progressive waves travel in a bounded medium with the same speed but in opposite directions then by their superposition a new type of wave is produced which appears stationary in the medium. This is .called standing wave. Let a b the amplitude, o angular velocity, k constant and x displacement, then equation of standing wave is                 \[y=a\sin \,\,(\omega \,t-kx)\] Given, equation is                 \[y=0.3\sin \,\,(314\,t-1.57\,x)\] On comparing the two equations, we have                 \[\omega \,t=314\,t\] and \[k\,x=1.57\,x\]                 \[\Rightarrow \] \[\omega =314\] and \[k=1.57\] \[\therefore \] velocity \[v=\frac{\omega }{k}=\frac{314}{1.57}=200\] unit


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