Manipal Engineering Manipal Engineering Solved Paper-2011

  • question_answer
    An alternating voltage \[E=200\sqrt{2}\sin (100t)V\] is connected to a \[1\,\mu F\] capacitor through an AC ammeter. The reading of ammeter is

    A)  10 mA                                 

    B)  20 mA

    C)  40 mA                 

    D)         80 mA

    Correct Answer: B

    Solution :

    Given\[E=200\sqrt{2}\sin (100t)\]                            ... (i) Comparing Eq. (i) with                 \[E={{E}_{0}}\sin \omega t\] Peak voltage\[{{E}_{0}}=200\sqrt{2},\,\,\omega =100\]                 \[C=1\mu F=1\times {{10}^{-6}}F\] Reading of ammeter,\[i=\frac{{{E}_{rms}}}{{{X}_{C}}}\]                 \[=\frac{{{E}_{0}}{{\omega }_{C}}}{\sqrt{2}}=\frac{{{E}_{rms}}}{1/\omega C}=\frac{{{E}_{0}}\omega C}{\sqrt{2}}\]                 \[=\frac{200\sqrt{2}\times 100\times 1\times {{10}^{-6}}}{\sqrt{2}}\]                 \[=20\times {{10}^{-3}}A\]                 \[=20\,\,mA\]


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