2. Solved Papers
  3. BHU PMT

BHU PMT BHU PMT (Mains) Solved Paper-2010

  • question_answer
    A metal wire of linear mass density 9.8 g/m is stretched with a tension of 10 kg-wt between two rigid supports 1 m apart. The wire passes at its middle point between the poles of a permanent magnet and it vibrates in resonance when carrying an alternating current of frequency v. The frequency v of alternating source is

    A)  50 Hz                                   

    B)  100 Hz

    C)  200 Hz                                 

    D)  25 Hz

    Correct Answer: A

    Solution :

                     Frequency, \[f=\frac{1}{2l}\sqrt{\frac{T}{\rho }}\] \[=\frac{1}{2\times 1}\sqrt{\frac{10\times 9.8}{9.8\times {{10}^{-3}}}}\] \[=\frac{1}{2}\sqrt{{{10}^{4}}}\] \[=\frac{100}{2}=50\,Hz\]            


You need to login to perform this action.
You will be redirected in 3 sec spinner