JEE Main & Advanced Physics Wave Mechanics Question Bank Progressive Waves

  • question_answer
    A transverse wave is described by the equation \[Y={{Y}_{0}}\sin 2\pi \left( ft-\frac{x}{\lambda } \right)\]. The maximum particle  velocity is four times the wave velocity if [IIT 1984; MP PMT 1997; EAMCET; 1998; CBSE PMT 2000; AFMC 2000; MP PMT/PET 1998; 01; KCET 1999, 04; Pb. PET 2001; DPMT 2005]

    A)            \[\lambda =\frac{\pi {{Y}_{0}}}{4}\]                               

    B)            \[\lambda =\frac{\pi {{Y}_{0}}}{2}\]

    C)            \[\lambda =\pi {{Y}_{0}}\]      

    D)            \[\lambda =2\pi {{Y}_{0}}\]

    Correct Answer: B

    Solution :

               Comparing the given equation with \[y=a\sin (\omega t-kx)\], We get a = Y0­, w = 2pf, \[k=\frac{2\pi }{\lambda }\]. Hence maximum particle velocity \[{{({{v}_{\max }})}_{particle}}=a\omega ={{Y}_{0}}\times 2\pi f\] and wave velocity \[{{(v)}_{wave}}=\frac{\omega }{k}=\frac{2\pi f}{2\pi /\lambda }=f\lambda \] \[\because \,\,\,{{({{v}_{\max }})}_{Particle}}=4{{v}_{Wave}}\] Þ \[{{Y}_{0}}\times 2\pi f=4f\lambda \] Þ \[\lambda =\frac{\pi {{Y}_{0}}}{2}\].


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