CMC Medical CMC-Medical VELLORE Solved Paper-2012

  • question_answer
    In a series L-C-R circuit, having C = 2uF, L = 1 mH and R = 10\[\Omega \] when the current in the circuit is maximum at that time the ratio of energies stored in the capacitor and the inductor will be

    A)  1 : 2                                      

    B)  2 : 1

    C)  1 : 5                                      

    D)  5 : 1

    Correct Answer: C

    Solution :

                    Current will be maximum in the condition of resonance, So,          \[{{I}_{\max }}=\frac{V}{R}=\frac{V}{10}A\]         So, energy stored in the coil, \[{{E}_{L}}=\frac{1}{2}L{{({{I}_{\max }})}^{2}}=\frac{1}{2}L{{\left( \frac{E}{10} \right)}^{2}}\] \[=\frac{1}{2}\times {{10}^{-3}}\left( \frac{{{E}^{2}}}{100} \right)=\frac{1}{2}\times {{10}^{-5}}{{E}^{2}}J\] Also, energy stored in the capacitor, \[{{E}_{c}}=\frac{1}{2}C{{E}^{2}}=\frac{1}{2}\times 2\times {{10}^{-6}}{{E}^{2}}J\]       \[={{10}^{-6}}{{E}^{2}}J\] \[\therefore \] \[\frac{{{E}_{c}}}{{{E}_{L}}}=\frac{{{10}^{-6}}{{E}^{2}}}{1/2\times {{10}^{-5}}{{E}^{2}}}=\frac{1}{5}\]


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