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12th Class Physics Alternating Current / प्रत्यावर्ती धारा Question Bank MCQ - Alternating Currents

  • question_answer
    A series LCR circuit with \[R=20\text{ }\Omega .,\text{ }L=1.5\text{ }H\]and \[C=35\mu F\,\]is connected to a variable frequency 200 V AC supply. When the frequency of the supply equals the natural frequency of the circuit, the average power transferred to the circuit in one complete cycle is:

    A) 200 W                          

    B) 2000 W

    C) 100 W                          

    D) 4000 W

    Correct Answer: B

    Solution :

    (b) 2000 W If the frequency of an AC source equals the natural frequency of the circuit, the impedance                  \[Z=R=20\,\Omega \] The average power dissipated per cycle, \[{{P}_{av}}=\frac{V_{rms}^{2}}{Z}=\frac{V_{rms}^{2}}{R}=\frac{{{(200)}^{2}}}{20}=2000\,W\]


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